If you develop with WordPress and are handy on the command line, I highly recommend installing and using WP-CLI. https://developer.wordpress.org/cli/commands/
To update a user’s password on the command line:
Change directory to the root of your WordPress site.
wp user update <user> —-user_pass=<pass>
Where <user> is the email address of the user and <pass> is a cleartext password that will be encoded and stored for the user.