Answered question
how do i apply a referral code that was texted to me?,,I still am waiting for SIM to arrive.
I havent activated my plan yet as I just ordered the SIM card.
You use it when you activate your plan. Once you get your sim card, and are ready to activate your plan, you will have an opportunity to enter the referral code.
Other answers
When you activate the SIM you will be asked if you have a code and you can enter it there.
When you activate your SIM card, there will be an option to enter your referral code.