The program will process data manually entered via 'Forms' mode. However, it won't process data that has been overwritten. So, if TurboTax enters information from what you answer during the Q&A, and then you go into 'Forms Mode' and change that entry, the return may not e-file and any accuracy warranties are voided.
If you're adventurous, you can even prepare your return in Forms Mode, but we don't recommend it. You may miss obscure credits and deductions you qualify for, and you may forget to report things that will come back and haunt you later.
