This is a basic tutorial on how to use the Magento 2 Permissions System to reset an administrator’s password. This can be useful if you have changed Magento service providers or have had and employee leave your company.
Login to Admin and navigate to System > Permissions > All Users
Next, simply click on the user you want to update.
On the User Edit page, be sure to create a strong unique password and input it in both password fields. You will also be required to enter your current password to perform the update. Click Save and inform your user of the change.