They should not see your password. If they do they have shit security and are untrustfull.

Thats why its important to have separete passowrd for accounts that stores money.

Sometimes, in free time i do some airdrops. Login with mail and password on multiple sites and multimple shitexchange to utilize those coins not listed on major exchanges (alwais same mail and passowrd - those are shitaccount that does not store money). Once after registrating on new ICO mail from one exchange come in that someone just logged it. So ICO's by airdrops are collecting login and passowrd entered and use them on dozens exchange hoping to find matching one. Thats why i strongly suggerst to have seperate mail and seperate password for accounts that store money or are important for you.