When you e-file, there is no physical signature. You sign electronically by entering your 2021 AGI or PIN. Assuming you have your spouse's agreement to file jointly, you can enter that and e-file. Your 2021 AGI is on line 11 of your 2021 Form 1040. If you filed a joint return for 2021 that amount is the same for both of you.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**