Creating SQL Login in an AlwaysOn SQL node

Hello,

I have a 2 node SQL cluster for AlwaysOn availability groups.  I will be using the group listener for an application that will create the database but need to provide a SQL login for the authentication.  If I create a sql login on the SQL node that is currently the primary, how will this account get created on the secondary node?

I'm looking for some for how to handle this the best/correct manner. 

Thank you,

Rumi