Chainlink Automation

Execute one or more functions of the contract automatically according to a fixed time.

Deploy a contract and obtain the address and ABI.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol";

contract erc20 is Initializable, ERC20Upgradeable, OwnableUpgradeable {
    using SafeERC20Upgradeable for IERC20Upgradeable;

    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }
    address erc721;
    function initialize() initializer public {
        __ERC20_init("ZombineCoin", "ZTC");
        __Ownable_init();
    }
    function setErc721(address erc721_)public{
        erc721=erc721_;
    }

    function mint(uint second) public  {
        _mint(msg.sender, 100*1e18*second);
    }
    function balance()public view returns(uint256){
        return balanceOf(msg.sender);
    }
    function approveMint()public{
        approve(erc721,100000*1e18);
    }
}

Open Chainlink Automation https://automation.chain.link/goerli
Select "time-based" as the trigger and enter the contract address.
Select the function name to be automatically executed and enter the parameters.
Select the frequency of execution.

This is a cron expression that can be converted using a tool.
http://cron.ciding.cc/
Choose a name and store some link tokens.