This isn’t something you’d do directly with Local, and is more of a WordPress question, so I moved it to the “WordPress Questions” category.
Basically, you’ll want to change the user settings within WordPress. This blog post goes into a few different options:
The above post mentions PHPMyAdmin. Local has Adminer which is pretty similar, and can be opened using the link in the “Database” tab.
Another option is to manage WordPress’ users with wpcli:
In particular the create and update subcommands might be useful!