It's simple, just download the MyDigi app from the App Store or Google Play Store, or update it to the latest version. On logging in to the app you'll be able to view your tier and start enjoying rewards.
MyDigi Rewards Support
How do I access MyDigi Rewards?
Why can I no longer see my membership tier?
We have suspended the membership tier from 1st July 2021 to give way to a new loyalty program. Exclusive benefits for gold and platinum members has also ended. However, you can still enjoy other rewards available on the MyDigi shop.