You can set an amount of gas tokens to receive on destination chain. For example, if you are transferring from EVM to Aptos, then you can choose to receive some APT on Aptos after the transaction is complete. The token is paid for by the user on the source wallet and is transferred through to the destination.
If you are transferring from EVM to Aptos, you can set up to 1 APT (MAX value) to receive on destination.
You can choose one of the 3 options (NONE, MEDIUM, MAX) or enter a custom amount in the textbox.
You will see total gas cost to be deducted from source chain at the bottom of the window.