I deactivated my account. How do I reactivate it?
You can reactivate your Facebook account at any time by logging back into Facebook or by using your Facebook account to log in somewhere else.
Remember that you’ll need to have access to the email or mobile number you use to log in. If you can’t remember your password, you can request a new one. If you can’t access the email associated with your account, learn how to reactivate your account.
Source: https://www.facebook.com/help/250563911970368?helpref=hc_global_nav