I entered my password on a fake login page. What now?

Reviewed answer

Treat that password as exposed and change it through the real service now.

Open the service's app or type its known address yourself. Change the exposed password, even if you did not press Submit.
Change that password anywhere else you reused it, starting with email and financial accounts.
Sign out other sessions, check recovery details, and enable two-step sign-in. Use official account recovery if you cannot sign in.

Get help if

Someone changed your recovery details, sent messages, made purchases, or locked you out.