If you have forgotten your phone password and want to unlock it, you will have to restore your device to its factory settings. Then you can set it up again and set a new screen lock.
However, all data on your phone will be erased and cannot be restored. It is recommended that you confirm whether you have backed up your phone data on the cloud or by other means. It is also recommended that you confirm whether you or someone else has changed the PIN/password. If you still cannot recall the password, refer to last Question to restore your device.