Type into a PDF form that refuses to let you type

You download a form, click the box next to "Full name", and nothing happens. No cursor, no highlight, no typing. The document is not broken and you have not missed a setting — the form has no fields in it.

Two kinds of document look identical here

An interactive form contains AcroForm field objects: named, typed widgets for text, checkboxes, radio groups, dropdowns, and signatures. Each has a rectangle, a name, a value, and appearance settings. Your reader knows a click at those coordinates means "focus this field".

A flat form contains none of that. It is page content that happens to depict a form — boxes, rules, and labels drawn as lines and glyphs, or one large scanned image of a printed page. There is nothing to click because there is nothing there. A large share of forms in circulation are flat, because they were designed for print and scanned back in, or exported from a layout tool that never added fields.

Telling them apart takes a second: press Tab in your reader. If focus jumps between blanks, the fields exist. If nothing moves, they do not.

If the fields exist, use them

Interactive forms should be filled through the field objects rather than by drawing text on top. The form filling tool reads the field definitions, presents them, and writes your values back into the correct objects.

That matters for reasons beyond convenience:

• Field values are stored as data, so the recipient's system can extract them automatically instead of reading the page.
• Validation rules, formatting, and calculated fields keep working.
• Checkboxes record a real on or off state rather than a drawn tick.
• Multi-line and auto-sizing fields lay out text the way the designer intended.

If a field is greyed out or refuses input, the form may be locked by permission flags or already flattened in part. That is a different problem from having no fields at all.

If there are no fields, place text instead

For a flat form, the only correct approach is to add new content at the right coordinates. The PDF editing tool lets you position text boxes on the page and place ticks, dates, and initials where the printed layout expects them.

Getting a result that looks filled in rather than annotated comes down to a few details:

• Match the type size. Sample the size of the printed labels and set your text a touch smaller. Text noticeably larger than the form's own type looks wrong immediately.
• Sit on the baseline. Align the bottom of your text with the printed rule, with a small gap. Text floating above the line or overlapping it is the giveaway.
• Pick a neutral face. A clean sans-serif reads as typed. A script or decorative font reads as a mistake.
• Use black, not near-black. Grey text photocopies and faxes badly, and some processing systems threshold it away entirely.
• Respect the boxes. In character-per-box forms, place each character separately at the box centres rather than typing a word across them.
• Tick, do not scribble. A simple check or cross inside the box beats a drawn mark that spills over the border.

If the form is a scan and you also want the finished document to be searchable, run optical character recognition over it as described in the OCR guide. Your added text is already real text; recognition takes care of the printed part.

Finish by flattening

Whichever route you took, the last step is the same and it is the one most people skip.

Until you flatten, the values you entered are separate objects layered over the page: field values in the case of an interactive form, annotations or free text in the case of an edited flat one. That means a recipient can clear them, drag them, or — depending on their reader's print settings — print the form blank.

Running the finished document through the flattening tool merges everything into the page content. After that, the completed form displays and prints identically everywhere, and the values cannot be edited without altering the page itself.

Keep an unflattened copy for yourself if you expect to make corrections. Flattening is deliberately irreversible.

A quick order of operations

1. Press Tab to find out whether real fields exist.
2. Fill the fields if they do; place positioned text if they do not.
3. Add the date and any initials, matching the form's own type.
4. Sign last, after everything else is complete.
5. Flatten, then reopen the output and read it as the recipient will.
6. Check that nothing you typed has drifted, clipped, or landed in the wrong box.

Every one of those steps is ordinary page manipulation that a browser can do locally, which is worth insisting on — completed forms are, almost by definition, full of exactly the personal details you would not want to upload to an unknown service in order to type them.