As part of close, you'll need to sign your mortgage documents (if applicable) as well other documents relating to the transaction close such as title insurance, final escrow closing statement and HOA agreements (if applicable).
Most of these closing documents have to be signed in person (not electronically). This will generally be done at the escrow agents' offices a few days before closing. In special circumstances, these documents can be overnight mailed to and from the escrow agent, although this will also require a notary public to notarize the documents at signing.