TWM shows your own World of Warships session in an overlay for streaming: battles, wins, average damage and average base XP. It keeps your Wargaming account ID, nickname and realm, the battles of your sessions and your account's battle counters for confirming them. Wargaming's data is kept at most 30 days, closed sessions 30 days after they close, and your account 180 days after your last activity. You can delete everything at any time.
To link your account you log in with your Wargaming ID on Wargaming's own page; TWM never sees your email address or password