I had a similar problem when completing a form Roy. There may be an easier method but I failed to find one.
I opened the form in Preview > Markup > and entered "Text Boxes" where I had to fill in the information required on the form. A little tedious but once I got the hang of it it wasn't a problem.
The great thing about this technique is that you can save the Preview created document and then use the data again when you have to complete the same form in the future.
This is very useful when completing the Blue Card application form.
Roy Rainford 