Local Authentication
The default authentication method is username and password, called "local authentication". This method available on all instances and can be used by all users unless the Domain Administrator has disabled it.
Passwords have default minimum standards, such as a minimum length of 8 characters. They are hashed and salted using the argon2 algorithm. This is a one-way hash function, which means that it is not possible to recover the original password from the hash. This is an industry standard for password hashing.