Removing Text from Message Body in a Form

[DeniseD]

I have created a form and in order to allow users to attach a document to
this form, I understand I must include the Main Message Body field in my
form. So I have added the Main Message Body field, but this field contains
what looks like my old signature. I removed my signatures and even my contact
information, but this signature information remains in the Main Message Body
field. Is there a way to remove pre-existing text from the Message Body? OR
if you know of any work around. I tried hiding the Message Body, but then
the attachment feature does not work.

Thanks!