I put 1 wrong number in my social security number and i already an efile on my federal tax return

If you filed your return with the incorrect Social Security Number, it will most likely be rejected. You will then have the opportunity to correct the error and resubmit the return.

https://ttlc.intuit.com/replies/3300281

So post back if it gets Accepted with a wrong ssn.

is it better to wait for the rejection or to file at 1040X? given that the issue is simply changing the social security number.

WHEN the return rejects you can make the change and refile ... you  CANNOT amend a return that was never accepted.