You can force an ssh client to use only password authentication when public key authentication is also configured by using the -o PreferredAuthentications=password
option when connecting to the server.
For example:
ssh -o PreferredAuthentications=password user@server
This option tells ssh to only use password authentication and ignore any public key authentication that may be configured. The ssh client will prompt you for the password for the specified user account on the server.
Keep in mind that password authentication is considered less secure than public key authentication, so it’s recommended to use public key authentication whenever possible.