@Bgemm21 You add them when you upgrade or take out a contract with EE as there is a field you put the code in to. Or you call customer services within 30 days of taking out the contract have have them add this to your tariff. You can not add them yourself after you have already started the contract.
To contact EE Customer Services dial 150 From your EE mobile or 0800 956 6000 from any other phone.
