Short answer
Yes. You can buy more data or change to a plan with more data in the app.
Buy more data
Open the app.
On the main screen, tap Show all available packages or choose a quick extra-data option.
Confirm the purchase.
Important
One-time extra data does not cancel or replace your subscription. If auto-renew is ON, your subscription may still renew on its schedule.
Subscription plans
You can manage your subscription in:
Settings → Manage Subscription.
Data packs are one-time purchases.
Subscription-based renew automatically.