If you send people a Word document form with protection activated, the recipients can't do anything to it other than type text into the form fields. You probably don't want anyone to unprotect the form and might even have given the form password protection.
What if someone wants to add an image, such as his or her .JPG signature? Here's how to make that possible.
Before protecting the form, add a section break shortly after the last form field but before where someone might want to add a signature or other image.
For Word 2007 or later, click Page Layout, Breaks, Section Breaks, Continuous. For Word 2003, select Insert, Break, Continuous.
When you activate protection on the document, protect only the section with the form fields. You'll see an option for which section to protect - make sure the box is unchecked next to section 2 or whatever section contains the image area.
Then, anyone who opens your document can only put text into form fields in the protected section, but can make changes, such as inserting a graphics file, in the non-protected section.