Okay, If you want to use Matic in trust wallet first of all you need to create a multi-coin wallet there(if you have no multi-account). Then you can easily add Matic coin to your coin list, also you can send and receive Matic there. If you have imported your MEW private key at Trust wallet, You can't able to use the Matic network there. Because MEW only supports ERC20 based coins.