Calvin_BT: I am using MacBook Air 13-inch 2017 running Catalina 10.15.7

Loner T: Are you using any third-party APFS software? Are Bootcamp drivers installed?

Calvin_BT: No just Boot Camp Assistant, I donâ  t know where to install boot camp drivers

Loner T: Download and install Windows support software on your Mac - Apple Support

Calvin_BT: When I install Windows, it Automatocally Downloads Windows Support Software

Loner T: If you reboot and hold Alt/Option key,  what are the available options

Calvin_BT: Oh great, I just remove the Windows Partition without noticing something, I will take a photo soon

Calvin_BT: The problem still persists, it is below:

Loner T: What happens when you select the Macintosh HD icon?

Calvin_BT: It boots up to macOS as usual

Loner T: What happens when you select Windows? Does it boot Windows properly? 

If your issue is not being able to see/select macOS from Bootcamp Control Panel, then you have an issue with Bootcamp drivers. Can you describe how you installed BC drivers?

Calvin_BT: It boots to Windows properly.

Calvin_BT wrote:

I donâ  t know where to install boot camp drivers

Loner T: After you download the BC drivers, switch to Windows, run setup.exe from the Bootcamp folder. Report any errors.