Stamp with thre (3) digital signature blocks plus additional information

We need a streamlined method for approving and processing invoices from our vendors and so I thought a stamp would be a perfect fit.

Is there a way to create a stamp so that I can enter a PO#, a Work Order#, a vendor #, and 3 signature blocks that can be signed by the respective individuals responsible for signing the document? I have the first three lines working, however, I cannot figure out the digital signature blocks.

TIA