Two very different documents get called forms. One has real fields built into it — click and type. The other is a printed layout with lines drawn on it, which needs text placed on top. This handles both, and tells you which one you have, because the difference determines what will happen when you type.
For a real form, the fields are found and highlighted, and the count is stated up front: how many blanks, and how many of them the form actually requires. Tab moves through them in reading order, which is right almost always. The list beside the document doubles as a progress view — click a row to jump to that field.
Nothing is marked as a problem until you press Download. Flagging every empty box the moment the document opens is a common pattern and a bad one: it turns a form into a wall of red before you have done anything wrong. The check belongs at the end, and at the end it names exactly which needed answers are still blank — then lets you download anyway, because sending an unfinished form is a normal thing to do.
The last question is the one most tools bury under the word “flatten”. Do the answers stay editable, or not? Framed properly it is easy: permanent if you are sending it off as final, still fillable if someone else has to add their part. That is a question about who gets the document next, so that is how it is asked.
One honest caveat, named rather than discovered: a form with automatic calculations does not compute here — your answers are kept, but the totals stay as they were, and the field says so rather than letting you assume. The older XFA kind of form is declined with a plain explanation, because half-filling one of those is worse than a clear refusal.
On a phone the flow changes shape without losing anything — one blank at a time, in a control you can actually hit, with your saved signature offered at the bottom, and download-then-share waiting at the end.