If a PDF has fillable form fields, select the Form fill tool. The fields appear as editable inputs directly on the page: text boxes, checkboxes and so on.
Fill in or change as many fields as you like, then click Apply N form changes, where N is the number of fields you changed, to save them all at once as a new version.
You can also ask the agent to “Fill this form”. Like your own edits, what it fills in is saved as a new version you can undo.