Login method
You give the seller your account login and they buy it on your account. Fastest, and the seller does everything.
Change your password afterwards.
Player ID
You give only your in-game ID. The seller sends the top-up straight to it — they never touch your account.
Redeem code
The seller sends you a code and you redeem it yourself, in the game or on the official site.
Each seller says which method they use. Pick the one you are comfortable with.
