Adding Text with the Typewriter Tools
Use the 
Typewriter tool or the 
Typewriter Box tool in the Advanced toolbar to add text at any suitable place on a PDF page. The Typewriter tool enters text directly at the cursor position. The Typewriter Box tool puts the text into a movable box. When the PDF is saved, the entered texts become selectable objects, unlike texts entered as annotations, e.g. with the Text Box tool.
Text can also be pasted onto a Typewriter tool cursor or into a typewriter box. That means text blocks can be copied from Normal or Searchable PDF files and pasted into other PDF pages in the same or different documents. Document Assembly view is useful for such operations.
As text is entered or pasted, in-place spell checking will be performed if it is enabled under Edit > Preferences > Spell Check. Spell checking cannot be run explicitly on typewriter tool text.
To move a typewriter box, select one of the Typewriter tools and click inside the box. Double click to edit the text. You can also move text entered by the Typewriter tool in the same way.
For more detail on the differences between typewriter texts and box tests, see Text Box.