Requesting Digital Certificate from signers

I create a fill and sign document, and I want to request my boss and CEO to sign with their digital Certificates using Adobe Sign flow, so I receive the document back signed with digitalid after being on the flow.

In can request all type of signature but can not request signing with digital ID. Also my boss is receiving and aobe sign link, where he coud sign with initials or name but cannot apply a digital certficate on document. Is it possible?

Thank you,

Alexandru M