I already filed but just received a w2 from an employer for 330.00 that was not expected. My employer said it was from 2022 wages but check was not issued till 2023. Help

If the date on the W-2 is 2023, then you must amend your already filed tax return to add the W-2. You must wait until your tax return is accepted or rejected by the IRS. If rejected, you can make the correction and resubmit it. If accepted, you must wait until your return is fully processed by the IRS and you receive your refund if you are getting one. You can then prepare an amended return to make the change. Amended return forms are expected to be available by mid February. Do not make any changes to your original return until you begin your amended return. 

If the date on the W-2 is 2022, then you would have to amend your 2022 tax return.