system
A chat on subreddit /r/pcmasterrace
human
Can you explain to me like I’m an idiot how I would go about this when I bought my pc and it came pre assembled and pre loaded and I can’t seem to find a disk or anything! I’m horrible at throwing away stuff like that so I’m confident I would’ve put it in the cd case, I mean I still have the cd for my printer from high school.
gpt
Download the Windows 10 / 11 ISO from Microsoft. Burn it to a flash drive, reboot your PC and boot off that flash drive. Follow the installation prompts and choose to format the drive you're installing Windows to.

Your Windows license is either tied to your Microsoft account, or is embedded in the system you bought and is digital. Either way it's a really good idea to tie your Windows licenses to a Microsoft account so you don't have to fuck with calling them if you change hardware.