Compilation error on 0.8.7

Why I am getting compilation error when I am using push member function for uint[] arr.

pragma solidity 0.8.7;

contract HelloStorage{
    uint[] storageArray;

    function addValue(uint value) public
        storageArray.push(value); // Adding value to storageArray
       uint[] storage storageArray;

        memVar.push(11); // Why this line giving error "member push is not available in uint[]256 memory outside of storage";
        storageArray = memVar;
    function display() public view returns (uint [] memory )
        return storageArray;