Email FIllable Form with two Signatures

I have created a fillable pdf that requires signatures from two different parties. I tested out the form: filled out some of the fields, signed one of the signature fields, then emailed the form to a different account and opened it on a different device. I was able to still fill out the fields and sign, however, some of the fields did not maintain their Form. For example, I had a field for a date that would pop up a calendar and the date form: d mmm yyyy; once the form was emailed the field Form "Date" was no longer applicable and the field was only a general text field. How can I prevent the field Forms from being stripped after signature and emailing?