The right letter writing app depends on the letter. This finder covers the apps writers use for personal and business letters, from AI drafting and grammar assistants to distraction-free editors, note-taking apps and real-time collaboration. Pick what you are writing, your platform and your price, and the matching apps appear below.
What are you writing?
Platform
Price
Best Writing Assistant
Flags typos, overused words and passive voice as you write, and its GrammarlyGO feature can generate a letter personalised to who you are writing to. Grammarly Pro is $29.95 per month or $139 per year; the free plan is limited.
Best Generative AI
Tell it who you are writing to and the voice you want, and it generates a draft letter you can refine with follow-up prompts. Free version available; the paid version costs $20 per month.
Platforms: Web, Mobile
Best For Adding Pictures To Your Letters
Drag-and-drop interface for adding infographics, images and multimedia to a letter, with templates for letters, resumes and more. No built-in writing assistant. Canva Pro is $6.49 monthly or $54.99 annually; the free version is limited.
Best For Apple Devices
Clean, simple note-taking that comes with every Apple device and syncs across them. Supports bullet points, numbered lists, tables and password protection, but has no collaboration or version history. Free.
Platforms: iOS, Mac
Best For Businesses
Word processor inside the Zoho CRM dashboard, so you can write letters and share them with your team alongside Zoho Sheet and Zoho Show. No writing-error checking and not available offline. The standard plan costs $20 per month.
Platforms: Web
Best Markdown Editor
Distraction-free Markdown editor with focus mode, writing goals and dark mode. Less suited to very large documents and has no templates. Costs $49 for Mac and $29 for Windows.
Platforms: Mac, Windows
Best Barebones Writing App
A more barebones alternative to IA Writer with a blank screen and nothing else, so ideas flow without distraction. Free, with no paid plan.
Platforms: Web
Best For Developers
Markdown editor that integrates with React applications, with a simple toolbar and a plugin for images, stickers and emojis. No mobile app. 100 percent free.
Platforms: Web
Best For Large Documents
Affordable, distraction-free writing app for Mac that handles large documents without lag. Does not support Markdown editing and has no mobile app. Costs $4.99 for a lifetime plan.
Platforms: Mac
Best WYSIWYG Editor
WYSIWYG editor with a simple dashboard, font options, cloud syncing and a Wizard AI feature. Integrates with OneDrive, Dropbox and Google Drive. Pasting in from another app can break formatting. The monthly plan is $6.99 and the free plan contains ads.
Best Integrations With Messaging Apps
Markdown editor for Apple devices with keyboard shortcuts and syntax highlighting that syncs across your Apple devices and exports directly into messaging apps. No pre-built templates. $10.99 once-off.
Platforms: Mac, iOS
Best For On-The-Go Writing
Lightweight note-taking app that works across devices and keeps your formatting, compatible with Markdown and Dropbox. Not as secure as most letter writing apps, so avoid storing sensitive information. Free, with an optional donation.
Platforms: Android, Mac, Windows, Linux
Best Free Trial
Distraction-free Markdown app for Mac, iPad and iPhone that syncs to iCloud and helps organise projects. Has a learning curve and is Apple-only. Free trial, then $40 per year.
Platforms: Mac, iOS
Best For Longer Letters
Popular writing program good for breaking up long letters into manageable sections, with helpful templates and research storage. Has an initial learning curve and no collaboration features. Free trial available; premium starts at $49.
Best Compatibility
Distraction-free word processor compatible with almost every writing platform, with word and character count tracking and customisable themes. Limited formatting and no collaboration. Free, with donations encouraged.
Platforms: Cross-platform
Best Free Plan
Checks grammar, punctuation and typos and suggests improvements to sentence structure, integrating with other platforms. Applying suggestions can be time-consuming. Free version available; premium is $60 per year.
Most Reliable Word Processor
Industry-standard word processor with basic spell check, proofreading, templates and collaboration tools. The interface can be overwhelming for a simple letter. Included with many operating systems, otherwise it can be expensive.
Best For Real-Time Collaboration
Lets multiple people edit the same letter simultaneously, with cloud auto-save and support for images and videos. Needs a reliable internet connection and formatting can shift on export. Free.
Platforms: Web
Best Readability Checker
Spots hard-to-read sentences, excessive adverbs, long words and passive voice, and gives a readability grade score. It does not check for writing errors and its suggestions can be rigid. Free.
Everything runs in your browser from a fixed list drawn from this guide. Nothing is sent anywhere.
Everything runs in your browser. Nothing is sent anywhere, and nothing is stored.
Match the app to the occasion. If you are sealing a business deal or sending a professional letter, a writing assistant like Grammarly or ProWritingAid catches typos, passive voice and weak phrasing before you hit send. If you are stuck on what to say, generative AI such as ChatGPT or GrammarlyGO drafts a personalised letter you can refine. If you want to add photos or a designed layout, Canva handles multimedia. For a quiet, focused space to write a personal letter, a distraction-free editor like Calmly Writer, Focus Writer or IA Writer keeps you out of the formatting weeds. And if you are writing with someone else, Google Docs handles real-time collaboration and cloud backup.
Three things mattered most in building this list. Value for money came first: the features were weighed against the price tag, and the list mixes free apps, premium apps and premium apps that come with a free version. Ease of use came next, because the best app is no help if its learning curve is punishing. Customisation came third, since writers need to format and tweak a letter to suit the recipient.
These are apps used day to day for real letter writing and client relationships, from landing business deals to informing clients of service changes and reaching out with cold-email letters. The recommendations come from hands-on use as a writer, editor and business owner rather than from vendor pitches.
If you want an easy-to-use app that handles large documents while checking your letter for errors, Grammarly is the safest all-round bet. You write inside the app while it lists suggestions on the right, and when you are stuck, GrammarlyGO can generate a personalised letter you can send with minimal edits. If you would rather draft from scratch, need a free option, or want a distraction-free space, the finder above narrows the field to the app that fits the letter in front of you.
There is no single best app, only the right one for the letter you are writing. For a polished, error-free business letter, Grammarly acts as a writing assistant and can even draft a letter with GrammarlyGO. For adding images and multimedia, Canva works best. For distraction-free personal letters, a barebones editor like Calmly Writer or a Markdown app like IA Writer keeps you focused on the words.
Several strong options cost nothing. Apple Notes comes free with every Apple device, Google Docs adds real-time collaboration, the Hemingway App checks readability, and Calmly Writer and Focus Writer give you a distraction-free space. Use the finder above and filter on Free to see them all.
Yes. ChatGPT and GrammarlyGO both use generative AI. Tell them who you are writing to, why, and the voice you want, and they generate a draft in seconds that you can refine with follow-up prompts. This removes the blank-page problem, though AI can occasionally produce inaccurate output that you should check.
WriteRoom handles large documents on Mac without lagging, even a 300-page paste. For long letters that need structure, Scrivener lets you break the letter into sections and store research alongside your draft. Both trade some simplicity for that extra power.
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About this guide: Written byBryan Collins, writer and founder of Become a Writer Today. Our recommendations are based on hands-on testing and independent research. Become a Writer Today does not accept payment for rankings or recommendations.