In-person signing is the paid feature which enable any user from your account to act as a signing administrator for the in-person parties and collect signatures from them by hosting a signing session. It can be initiated while sending PDF template for esignatures.
2. If you are sending the document to a new signer (email address not in your address book), click on 'Add New' button to add the name and email first. You can select 'Select this party as in person signer' to enable the in-person signing. You will also need to assign the in-person signing administrator. For in-person signer email address is not required.
3. After sending the template for the signing procedure for in-person signers via an administrator is the same as explained in the above article/document/link.
Recommendation: In-person Document Signing