This forum is for Acrobat/PDF not Excel. Signing Microsoft Office documents does not belong to this forum. If you convert Excel forms to PDF and want sign these PDFs, then it is a different story. Please, clarify what you're trying to do.
Hi Isakten, I understand that. It is a pdf form, the Excel files are inserted into PDF by using the attach file button. In this way the one pdf form acts as a kind of carrier for all of attachments (and that can be quite a few). This is a link to the form (I hope it works), the form is in Dutch but if required it would be no problem for me to make an English version.
One thing which is important; to activate the digital signature field you first need to to check the checkbox 'Bijlagen gezien' - this just means 'attachment viewed'
I am not an Excel or Excel-to-PDF conversion expert, so I do not know how Excel forms are converted to PDF form fields. With this caveat here's what I do know.
I never tried that myself but it could work. This looks complicated and it is but if you really want it you can try.