service principal

To create a service principal for accessing Azure resources (e.g. data lake) from outside, e.g. databricks

Azure Active Directory -> App Registration -> create a new registration

This gives you the app id, tenant id

On the page for the registration, go to Certificate & Secrets, Create a new client secret

This gives you the password / key

Also you need to grant access to the application. Go to the storage account for example, and through Control Access, assign a role (e.g. Storage blog contributor role) to the registered application. The application/registration is kind of a Active Directory  delegate (https://docs.microsoft.com/en-us/azure/active-directory/develop/app-objects-and-service-principals) so it can used like a account.