I have created a fillable form for my client. I added a signature field so that once signed the form could not be edited. HOWEVER she does not see the signtaure field. It acts like a regular text field on her end. I told her to look for the little red flag in the signature feild. She said she can just type in it and the Signature pop up box does not come up.
I do not know what version of Reader she is running. Could it be her Reader is just out of date?
You need to find out what she's using. What you describe is unusual and makes me think she could be using a non-Adobe PDF viewer.
Note that Adobe Reader cannot be used to sign a digital signature field unless the document has been Reader enabled, either by Acrobat Pro or LiveCycle Reader Extensions.