How to create admin and db based user in mongodb?

Admin User:

db.createUser(
    {
      user: "admin",
      pwd: "password123",
      roles: ["userAdminAnyDatabase","userAdmin","readWrite","dbAdmin","clusterAdmin","readWriteAnyDatabase","dbAdminAnyDatabase"]
    }
)

DB based User:

User who can access only a specific database.

db.createUser(
   {
     user: "myuser",
     pwd: "password123",
     roles: [ { role: "readWrite", db: "databasename" } ]
   }
);