Form 1040-C is not considered a valid return unless you sign it. You may have an agent in the United States prepare and sign your return if you are sick or otherwise unable to sign. However, you must have IRS approval to use an agent. To obtain approval, file a statement with the IRS office where you file Form 1040-C explaining why you cannot sign.
If an agent (including your spouse) signs for you, your authorization of the signature must be filed with the return.taxmap/instr2/i1040c-008.htm#
Generally, anyone you pay to prepare your return must sign it in the space provided. The preparer must also give you a copy of the return for your records. Someone who prepares your return but does not charge you should not sign your return.
If you have questions about whether a preparer is required to sign your return, please contact an IRS office.