Laptop as a pc monitor?

I have a pc and a laptop but no monitor can I use the laptop as a desktop onitor?

For this you need a laptop, which has a video (HDMI or VGA or DVI) input. But only a few have. Most have only one video output.

For this, the laptop would need a video input. Since such inputs are rarely installed but you could buy a Captcha Card to use this as a video input.

Otherwise, you could also use the image via applications, e.g. By remote desktop application, transfer. But you have to activate this first, so you'll need a screen to set it up for the first time.

Would be on the laptop a Linux distribution and on the PC too. I could easily access the PC via remote and remote control. For this a LAN connection is sufficient (NO WLAN!)

Conversely, that would also be possible so that I can access the laptop from the PC. But to use this as a monitor directly to show things is not possible.