about mic phone of mac mini

This

https://appleinsider.com/articles/18/10/30/frequently-asked-questions-about-the-2018-mac-mini-ram-storage-and-more

includes

" and a headphone jack —note that this is not a microphone port as well."

This

https://www.engadget.com/2018/11/16/apple-mac-mini-2018-review/

also says

Compared to previous Minis, you do lose the analog microphone input, but considering USB-based digital-analog converters are plentiful and effective, that's not a huge loss.

You will have to use a usb microphone or usb headset. Depending on what you need or use the microphone for, there are plenty of inexpensive options. I use a Samson GoMic with my 2018 Mac mini for web meetings and I have also used a Logitech usb headset with it and a Samson Meteor mic and all three work very well for FaceTime, Skype, MS TEAMs, Go2Meeting, Zoom, FCC.

Have you actually tried it with a late 2018 Mac mini to confirm? I just ask because I have not tried it with mine, and every technical review refers to line in via the 3.5mm jack as AWOL (and the optical audio input was dropped by Apple on their 3.5mm jacks on Macbook Pros a year or two ago as well).

I honestly have yet to use my Mac mini’s 3.5mm jack for anything - my speakers are fed via one of my Monitors with audio over DisplayPort.

Regardless, the inexpensive and plentiful USB microphones or headsets are so superior to anything analog I’ve ever used in the past, I cannot see why anyone would stick with analog. My cardiod/surround Samson GoMic was $30 on Amazon. With it taped on top of one of my monitors (with Velcro tape) I can walk around my home office and just speak from anywhere up to 10ft from the mic and it picks up my voice just fine.

Yes of course and from day 1! Works flawlessly, plug and play and with superb quality.

unless the headset connector support the apple headset with mic in type of 3.5mm minijack connectors where you can get a splitter to connect a mono mic in

then you have to purchase an usb mic

Yes.

No, incorrect. Any analog headset with mic will work with the headphone port.