Writing a document straight to PDF
Sometimes you need a short document and opening a word processor is disproportionate. A covering note, a receipt, a simple letter, a one-page statement, a list somebody needs in a fixed format — these do not need styles, templates or a document that will be edited again.
Typing directly into a PDF removes the intermediate steps. There is no document to save in one format and export in another, no application to wait for, and no risk that the recipient sees something different from what you wrote because their word processor substituted a font.
It suits anything where the content matters and the layout does not need to be elaborate. For anything requiring real design — a report with headings and figures, a document that will be revised repeatedly — a proper editor is still the right tool, and converting from Markdown or HTML gives you more control than typing plain text does.
Making a plain document look considered
A few conventions do most of the work. Keep line length moderate: text that runs the full width of an A4 page is genuinely harder to read, which is why books and newspapers use narrower columns. Leave generous margins rather than filling the page.
Break the text into paragraphs with space between them rather than running everything together, and put the most important information first. A recipient scanning a document decides in seconds whether they have understood it, and burying the point in the fourth paragraph is the most common reason short documents get misread.
Include the things that make a document usable later: a date, your name, and a subject line or heading that says what it is. A document that is clear today and unidentifiable in six months has failed at the part that mattered.
What a typed PDF gives you that a photograph does not
The text is real text. It can be searched, selected, copied, read aloud by a screen reader, and indexed by whatever system files it. A photograph of a handwritten note is a picture, and everything about it is opaque to software.
It is also far smaller. A page of typed text is measured in kilobytes; a photograph of the same page is measured in megabytes. Over a set of documents that difference determines whether they can be emailed at all.
And it is legible without qualification. Handwriting varies, photographs of handwriting vary more, and a document that the recipient has to squint at is a document that invites a follow-up question. For anything official, typed is simply safer.
Documents worth typing rather than formatting
A few kinds of document are almost always faster to type straight to PDF than to build in an editor. A covering note attaching something else. A simple receipt or acknowledgement. A written statement or declaration for an application. A short authorisation letter. A packing note. In each case the content is a few paragraphs and the layout is irrelevant.
What these have in common is that they are read once, filed, and never revised. The whole apparatus of a word processor — styles, templates, revision tracking, an editable source file to keep somewhere — exists to support documents that will change, and it is pure overhead for documents that will not.
The test is simple: if you cannot imagine editing the document again, there is no reason to create an editable version of it first. Type it, produce the PDF, send it, and skip the intermediate file you would only have had to tidy up later.
There is a related case where typing directly is not just faster but safer: documents you do not want carrying a history. A file created in a word processor accumulates an author name, a company, revision timestamps and sometimes tracked changes you thought you had removed. A document typed straight to PDF starts clean, which matters for anything sent to a party you are negotiating with.