I sent 20 xrp from poloniex to an adress but i checked on the blockchain and there is 0 balance after 2 hours from transaction, noting was received.
Also it says "Inactivated address".
The receiver should do something to activate the adress?
on poloniex it says "processing"
You suppose to see something like completed on the exchange and not processing. Processing means the withdrawal is not yet completed. But ripple transaction is fast and supposed not to take more than some seconds or minutes.
[You might be withdrawing XRP in the wrong way I think it should include the destination tag without it you won't receive anything from your wallet.
You do not need any tag to withdraw ripple to a noncustodial wallet. You will need the destination tag if you are sending the coin to an exchange or custodial wallet.