Hi JiaKF,
Thanks for visiting the Apple Support Communities.
To mirror your iPhone screen to your Mac, you will need to use the AirPlay feature. This is initiated on your iPhone, not your Mac. You can get the instructions on how to do it below, and in the Apple Support article on using AirPlay for mirroring, Use AirPlay to stream video or mirror the screen of your iPhone, iPad, or iPod touch - Apple Support:
Mirror your iPhone, iPad, or iPod touch to a TV or Mac
1. Connect your iPhone, iPad, or iPod touch to the same Wi-Fi network as your Apple TV, AirPlay 2-compatible smart TV, or Mac.
2. Open Control Center:
• On iPhone X or later or iPad with iPadOS 13 or later: Swipe down from the upper-right corner of the screen.
• On iPhone 8 or earlier or iOS 11 or earlier: Swipe up from the bottom edge of the screen.
3. Tap Screen Mirroring .
4. Select your Apple TV, AirPlay 2-compatible smart TV, or Mac from the list.
5. If an AirPlay passcode appears on your TV screen or Mac, enter the passcode on your iOS or iPadOS device.
To stop mirroring your iOS or iPadOS device, open Control Center, tap Screen Mirroring, then tap Stop Mirroring. Or press the Menu button on your Apple TV Remote.
If you are still unable to mirror your iPhone to your Mac, don't hesitate to respond back.
Cheers!