Syntax:
CREATE USER syntax for MySQL 5.7.6 and higher:

The CREATE USER statement creates new MySQL accounts. It enables
account authentication properties to be established. As of MySQL 5.7.6,
it is also possible to establish authentication, SSL/TLS, and
resource-limit properties, account password expiration, and account
locking and unlocking.

An account when first created has no privileges.

To use CREATE USER, you must have the global CREATE USER privilege, or
the INSERT privilege for the mysql database. When the read_only system
variable is enabled, CREATE USER additionally requires the SUPER
privilege.

An error occurs if you try to create an account that already exists.

As of MySQL 5.7.8, the IF NOT EXISTS clause can be used, which causes
the statement to produce a warning for each named account that already
exists, rather than an error.

For each account, CREATE USER creates a new row in the mysql.user
table. The row reflects the properties specified in the statement.
Unspecified properties are set to their default values.

Example 1: Create an account that uses the default authentication
plugin and the given password. Mark the password expired so that the
user must choose a new one at the first connection to the server:

CREATE USER 'jeffrey'@'localhost'
  IDENTIFIED BY 'new_password' PASSWORD EXPIRE;

Example 2: Create an account that uses the sha256_password
authentication plugin and the given password. Require that a new
password be chosen every 180 days:

CREATE USER 'jeffrey'@'localhost'
  IDENTIFIED WITH sha256_password BY 'new_password'
  PASSWORD EXPIRE INTERVAL 180 DAY;

URL: http://dev.mysql.com/doc/refman/5.7/en/create-user.html

