When interacting with a blockchain network, you'll need to pay network fees to submit transactions. Depending on the level of network activity and the price of the gas token, these transaction fees can vary from fractions of a cent to hundreds of dollars.
For a comprehensive overview of what gas is, see Coinbase's What are gas fees? article.
When bridging via Superbridge, you'll often want to make sure you have gas on the destination chain before bridging over any assets. If you don't have gas, those funds will essentially be stuck, as you won't be able to submit transactions on the destination chain.