I forgot my MacBook Air password and can’t connect to the Wi-Fi

You might need to do this via macOS recovery: In recovery you can click the WiFi icon in the top right corner to connect to a wifi net work, and then follow these steps

If you couldn’t reset your password using the reset options in the login window:

1. Start up from macOS Recovery.
2. While starting up from Recovery, you're asked to select a user you know the password for. Click “Forgot all passwords?”.
3. Follow the onscreen instructions, which vary based on your Mac setup. 
4. After you provide the information requested, you're asked to create a new password for your account. When done, click Exit to Recovery, restart your Mac, and log in with the new password.

If you couldn't use these steps to reset your password, follow the next steps while still in Recovery. You’re in Recovery when you see options to restore from Time Machine, reinstall macOS, and more:

1. From the Utilities menu in the menu bar at the top of the screen, choose Terminal. Or press Shift-Command-T to open Terminal.
2. In the Terminal window that opens, type resetpassword, then press Return. 
3. In the window that opens, choose a reset option, such as “I forgot my password” or “My password doesn't work when logging in.” Then click Next and follow the onscreen instructions.
4. After you provide the information requested, you're asked to create a new password for your account and any other user accounts. You can then restart your Mac and log in with the new password.

If you couldn’t use these steps to reset your password, continue to the next section.