## Account Abstraction Lesson 4: `PackeduserOperation` In this short lesson we are going to cover the `PackedUserOperation`, which was introduced and imported in the previous lessons. It is basically a collection of different types of information that together define an operation that a user wants to perform. Let's take a closer look. > ❗ **NOTE** The lines of code dealing with gas fees, limits, and verification - as well as `bytes initCode` - are to be ignored for now. ```js struct PackedUserOperation { address sender; uint256 nonce; bytes initCode; bytes callData; bytes32 accountGasLimits; uint256 preVerificationGas; bytes32 gasFees; bytes paymasterAndData; bytes signature; } ``` `address sender`: This is the address of our minimal account, the one performing the operation. `uint256 nonce`: This is a number that helps keep track of the sequence of transactions. It's a way to ensure each transaction is unique and not repeated. `bytes callData`: This is where we put the important stuff. For example, if our minimal account wants to approve spending 50 USDC tokens, this is where that information goes. `bytes paymasterAndData`: This can be used to customize who pays for the transaction. It might include details of another account that will cover the transaction costs. `bytes signature`: This is the digital signature of the sender, used to authenticate the transaction and prove that it was indeed created by the sender. So, in essence, this structure is a detailed blueprint of a transaction, containing everything needed to process and verify it on the blockchain. Take a moment to reflect on these concepts. When you are ready, move on to the next lesson.