-snip-
Also i didnt create the wallet , i was given it by the employer. (is it possible for him to change the pw afterwords?)
He can't but if he has the backup (
seed phrase or private key) or a copy of the wallet file, then he can still spend it whenever he want.
BTW, payment through a flash drive with a pre-created wallet is a red flag.
Note: Bitcoins aren't stored in the wallet, handling you a wallet doesn't mean you received the bitcoins.
It's stored in the blockchain which every non-pruned Bitcoin Node has.
The wallet only contains the necessary keys that can spend the coins that it can prove the ownership.
The correct way to receive your payment through Electrum is to create your own wallet (
instructions).
Use the receive tab to get an address, then send it to the employer so he can send the payment to that address.
Finish the deal after getting at least 1 confirmation (
more for high-risk transactions).