Capture Ideas on iPhone: A Fast Plain-Text Inbox
Ideas don't wait for you to open the right app and pick a folder. The fastest way to catch one on iPhone is a single running plain-text file: type it as one line, skip every formatting decision, and sort it out later. Here's how to build that inbox and keep it fast.
Quick answer
Keep one plain-text file as your capture inbox. When an idea shows up, open the file, add one flat line, save, and get back to what you were doing. No headings, no bullets, no filing — that all happens in a separate review pass, not at the moment of capture.
It comes down to speed. Speech and thought move at roughly 120-180 words per minute, while handwriting manages only 12-18 — a gap wide enough that any formatting decision made mid-capture is time an idea can slip away in. A single inbox with zero structure removes that decision entirely. This is the same principle behind capturing now and organizing later: the two jobs don't belong in the same moment.
Step-by-step
Start one file, not a folder structure
Resist the urge to set up categories before you've captured anything. One file means there's no filing decision to make when an idea shows up — you're not choosing between "Work," "Personal," and "Maybe Later" while trying to hold a thought in your head. Treat it the way you'd treat a throwaway scratch file: disposable-feeling on purpose, so nothing about opening it feels heavy.
Write one idea per line
Note-taking research backs this up: linear methods that record each thought as a short, flat line — sometimes called the sentence method — outperform anything that tries to impose hierarchy while you're still capturing. Structure is a review-time problem, not a capture-time one.
Resist formatting until review
No bold, no headings, no bullets while you're catching an idea. That's editing, and editing is a different task from capturing. Plain text earns its keep here too: a Markdown file is designed to stay fully readable even before it's rendered, so a flat list of unformatted lines is already useful the moment you write it, not just after you clean it up.
Save and get back to what you were doing
That's the whole point. The inbox exists so the interruption is as short as possible — type, save, done.
Common problems and fixes
"I forgot to write it down before I got distracted"
The fix is almost never a better app — it's fewer taps between having the thought and typing it. If opening your capture file takes more than a couple of taps, that's the friction losing you ideas, not your memory.
"My inbox is 200 lines long and I never look at it"
Put review on a schedule instead of relying on willpower to remember it exists. A daily plain-text habit works well here — pair the review with something you already do every day, so triaging the inbox (keep, turn into a real file, delete) becomes routine instead of a chore you keep deferring.
"My notes are scattered across three different apps"
That's exactly the case plain text solves: it's portable by design. One format, one file, readable in anything, with nothing proprietary to get locked into. Scattering happens when every app wants its own format — plain text sidesteps that by refusing to have one.
Doing this with Carets
This workflow asks two things of an editor: open and save fast enough that capture never feels like a task of its own, and keep files in a format that won't lock you in later. Carets is built around both. It's native on iOS and Mac rather than a web wrapper, so there's no load time standing between having the idea and typing it. Everything you write stays plain text and Markdown — the same inbox file you're jotting one-line ideas into today is still a plain, portable text file next year.
The organize-later half of this system is where Carets' files, projects, and tags carry the weight: once an inbox line proves it's worth keeping, move it into a project file and tag it, without ever having to make that call during capture. Carets isn't a task manager or a scheduler — it's the inbox and the archive, and it's honest about staying in that lane.
Carets is available on iPhone, iPad, and Mac.
Frequently Asked Questions
What's the fastest way to capture an idea on iPhone?
Open a single running plain-text file, type the idea as one flat line with no formatting, and save. The speed comes from skipping every formatting decision at capture time — you organize later, in a separate pass.
Should I use one file or many for capturing ideas?
One file. A single running inbox means you never have to decide where an idea belongs before you've even finished typing it — that decision is what slows capture down. Split it into projects or tags only after the idea has proven it's worth keeping.
Why plain text instead of a formatted note?
Plain text has no rendering step, no proprietary format to get locked into, and stays searchable years later regardless of which app you're using. Markdown's own design goal is that a plain-text file stays fully readable even unrendered, which is exactly what a capture inbox needs.
How do I stop my capture inbox from becoming a junk drawer?
Review it on a schedule — daily or weekly — and triage each line: keep, turn into a project file, or delete. The inbox's job is speed at capture time, not permanent storage.
Conclusion
A fast capture inbox comes down to two rules: no structure while you're catching an idea, and everything stays plain text so nothing you write is ever locked into one app's format. Once that habit sticks, the same single file scales naturally into a full plain-text writing system — the inbox just becomes the first stop.