Hi @Lai-YingChan,
If we're talking about Go Roam in Europe, then this should be automatic whenever you first make an outgoing call, text, or use data each day. You don't need to apply the charge, the billing system detects this automatically.
Hope this helps.
JonathanB
Mod tip! The author of a post can hit 'Accept as Solution', to highlight a reply that helped solved their query.
