Send transaction with self generator key using Metamask or any other web3 wallet

We are looking for a web3 developer to help us add functionality to use self generated keys to interact with our smart contract and send transactions. Currently, users need to confirm each transaction using Metamask, however, we need to add this extra option for users to either use self generated key or still use the current functionality. Please only apply to this job if you understand the task at hand.

Imoportant note: Please describe your recent experience with similar projects