@Chalena Darden Fully completed envelopes cannot be edited or corrected to add anything new to the completed envelope.
Whether or not your signature has an impact is difficult to determine from anyone’s standpoint outside of the need of that document. If it is expected that the document has you as a signer or counter-signer to make it approved, official, or legally enforceable is something that is specific to your situation, company or the specifics of the document. You can always send another envelope with the same base document to get the signature of the client as well as your signature to supercede the original envelope.