There are two ways to connect, and one is better
There are two ways to connect to Magento. The recommended route is to define an integration under System → Integrations in the admin and take an access token from there. The second is connecting with an admin username and password; that works too, but it hands the connection every permission the administrator account has.
The token route is better not only for security but for durability: when the administrator password changes the token is unaffected and the connection keeps working. A setup connected by password stops at every password change.