Use two-factor authentication to help strengthen the login process. Two-factor authentication means that you must provide something that you know (your password) and something that you have. There are several available such as –
In the case of Google Authenticator and Duo, after you log in to WordPress with your username and password you are then prompted for another code. Both Duo and Google Authenticator have mobile apps that either display a code or confirm the login. You can also receive the code via SMS. Yubikey is a USB device that you must have plugged in.