The fees paid on the Ethereum network to use the computational power of the platform are known as gas fees. There are several activities that require gas such as simple transactions like sending ETH among traders, using and launching decentralized applications, etc. This fee is paid using the native token of the Ethereum blockchain, Ether.
Gwei is the unit in which gas is consumed. It is the smallest unit of one Ether. One gwei is equal to 0.000000001 ETH. The amount of ETH required to pay during a single transaction is dependent on the resources being used to carry out the same as well as the congestion level of the blockchain.
Charging fees for every transaction curbs malicious actors from spamming the network, thereby helping in enhancing the security of the network. The lower the gas fees, the higher the time required for the transaction to get processed.