So you mean these people won't access the SAP system and they nee to enter data in something like an Excel sheet?
It looks like an interactive form (simple PDF file with the interactive function to enter data; data being saved inside the PDF itself). You need a license for generating the Adobe interactive forms.
How will they enter the PDF back into the SAP system? It's possible to send a mail from the PDF to SAP, or someone may manually load the PDF.
Embedding all this in a workflow, and loading the data into the SAP database (BAPI) should be possible without problem.
Could you elaborate more about what are the restrictions?