There are two ways to do this.

The most common method is to restrict the document for forms by going to the Developer Tab and choosing Restrict Editing > Editing restrictions (Filling in forms). The side effect of this method is that the user can't apply formatting or paste graphics into Rich Text CCs. If the form doesn't have any rich text CCs then this is the preferred method.

What do you mean you want to embed your logo? Insert > Pictures or Copy Paste both provide ways of getting a graphic into your document. Or are you asking how to insert a watermark behind every page.

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Andrew Lockton
Chrysalis Design, Melbourne Australia