By default, Magento 2 encrypts owner’s password using SHA-256 algorithm (have in mind that encryption methods can vary from version to version). The measures are taken to eliminate hackers ability to penetrate into your store database and stole the password. Thus, if you have forgotten or lost magento admin password, it can only be replaced with a new one, which in its turn will also be encrypted during the process.
UPDATE admin_user SET password = CONCAT(SHA2('xxxxxxxxNewPassword', 256), ':xxxxxxxx:1') WHERE username = ‘admin';
The admin password can be recovered with the default recovery system. Go to your Admin Panel and choose the ‘Forgot your password?’ link. Put in your email address and click the Retrieve Password button:
You will be sent a link following which you will manage to reset a current password: