Two Recipent's having same Name & same initials - Authentication

1. If there are two recipients and both their names are let's suppose R. Rose, and customer does not prefer Digital Authentication, document is being sent to R. Rose from Sales, and R.Rose from Legal department and both parties sign, how do you know which signature is from whom?

2. When a document is sent to a recipient's email Jane R. When Jane opens the email and while signing she can also "Type" her name as Rose while signing. Without Digital Signature  or Adhaar Authentication how to prevent the recipient from changing their names while signing? Otherwise how will the sender authenticate that Jane is signing the document (without Adhaar Authentication in eSignature)