I am using LaTeX to make a fillable PDF file.
I use the
\TextField command in the
hyperref package to get the fillable field in the PDF file.
In some places, I want to have a field which has a limited number of characters for input, e.g. the phone number or card number.
How could I realize this effect? I looked up the
hyperref package but failed to find any information for this effect.
Would anyone please give me some idea?