W-10s don't get "filed" anywhere. Its a request for a dependent care provider to provide their tax ID number. Nobody "files" it anywhere.
Did you mean where do I enter childcare provider(s)?
To enter child care expenses:
1.
Log into your account and
continue (if not already there).
2.
In the Search box (top right-hand
corner), type “child and dependent care”.
3.
Click on the Magnifying Glass
icon.
4.
Click on “Jump to child and dependent care” link high-lighted in Blue.
5.
Answer the Step-by-step
instructions.
