Change Format of a ADOBE PDF in SFP

Hello,

for me it is the first time i need to create a ADOBE PDF Form in a different format than A4.

I have the requirement to create a form for Visitor-signs (name / position / company) which should be printed from SAP CRM on a label writer.

Does one of you experts know how to change the Size of the ADOBE Form.

Thank you

Best regards

Manfred