I want to launch a candy machine, but I cover the cost of gas to mint the NFT. Therefore, the only thing the user pays is the price of the mint. Is this possible? If so how would I go about making this change in the config settings?
The Candy Machine doesn't allow that.
You can try playing with Octane, but I am not sure it will work: https://github.com/solana-labs/octane.
Andres is correct, the candy machine does not directly support it. Octane like he said could be one approach, a different one could be to partially sign the mint transaction in a backend with your Key and give this to the frontend where the user also signs it.
You would have to modify that TX in comparison to the default mint tx and set your wallet as fee payer instead of having the minter also pay the fees.
Please be aware that storing your keys on a webserver always comes with a higher risk.