How do I know if o signed my tax return

E-filing is your electronic signature. If you E-filed, and submitted your returns, then you have signed.

When I downloaded my return I didn't see my signature 

If you efiled there should be an Electronic Postmark page.  Probably near the end.  That is your proof and signature.  If you print out your return to give someone you will have to sign it in ink now.  

@heatherstalinski77 When you e-file your tax return there is no physical signature on the tax form.   Your "signature" was electronic when you entered your AGI.   If someone needs or requires a "signed" copy of your tax return then take a pen out and sign and date the Form 1040 on the line on page 2 that says "Sign here."

Ok thank u