Some people says that the wrost thing to do is leave your bitcoins in some exchange.
I have 200 usd of btcs in Payeer, it is a online wallet but it also has a exchange.
Do you recommend to me to move this bitcoin to a wallet like Electrum?
If you keep your coins like in exchanges like bittrex or poloniex or hitbtc or bitfinex etc you won't be having a problem. But it's always suggested that you keep your coins in a hard ware wallet for security purposes because exchanges might have be hacked or scam or something else, you cannot predict what will happen and when it will happen. So that's why hardware wallets are the best.