After you file

If you are picked for one of the 2 testing groups your return can be accepted for processing however the approval comes later after the return is processed.  It is possible to be approved prior to the official start date of 1/27 however don't hold your breath ... the refunds will still not be issued prior to that date.

 

https://refundtalk.com/irs-announces-the-start-of-e-file-test-batchhub-testing-for-2020/