How to add a second monitor for my MacBook?

Perhaps to better identify the 'build model year' configuration and the ports available

too, may help. ~ While I've two 'MacBook' models, both different. I can't tell by images.

• Connect a display to your Mac - Apple Support

https://support.apple.com/en-us/HT202351

• Use an external display with your MacBook Pro - Apple Support

https://support.apple.com/guide/macbook-pro/use-an-external-display-apd8cdd74f57/mac

• How to add a second screen to your Mac or MacBook | Macworld

https://www.macworld.com/article/233948/add-a-second-display-to-your-mac.html

[identify the exact mac build series model year vintage]

• Identify your MacBook model - Apple Support (this has -two other series links- within)

https://support.apple.com/en-us/HT201736

"This article lists MacBook models only. You can find similar information for MacBook Pro and MacBook Air."

• Identify the ports on your Mac - Apple Support

https://support.apple.com/en-us/HT201736

An idea may be to identify the MacBook (Which one of four? old-model-series: Is it?)

[Everymac.com has most Apple/Mac products with detailed tech specs on their site.]

• Mac & Apple Devices - EveryMac.com's Ultimate Mac Lookup

https://everymac.com/ultimate-mac-lookup/

Good luck & happy trails! ☺︎

This is not a 12" Retina MacBook.

I don't need any further information, but you posted to the wrong forum area. MacBook Airs have their own separate forum area. This forum area is for 12" Retina MacBooks made between 2015-2017.

I just sent you a picture: