Gas Limit refers to the maximum quantity you are willing to spend for a specific transaction. A higher gas limit means it is necessary a greater calculation power to execute the smart contract. Standard ETH transfer transaction requires a minimum Gas limit of 21.000 units.
On the Eidoo wallet, you can set the Gas price in the "Advanced Settings" on the top left part of the "Transfer page".
For further information regarding the Gas Price, we suggest you read the following article: