It depends on the lender, as some require the auto loan cosigner to be present at the closing of the loan. Other lenders may allow the co-signer to fax the documents back to them. If faxed, it may require the services of a notary to verify, and notarize the signature of the co-signer. Being a co-signer is a serious commitment and should not be taken lightly. If the loan is defaulted on, the co-signer will be on the hook for the loan amount. Check with the lender regarding their requirements and make sure the co-signer completely understands their obligations.