1
I presume Windows was pre-installed on the PC you purchased online, it is not a separately purchased retail Windows licence, is that correct?
If so, did the retailer provide you with a product key, possibly on the receipt for the PC or on a COA label on the back case of the PC.
2
I need to check if there is a pre-installed OEM licence on the PC.
Download the free ShowKeyPlus app from the Microsoft Store.
Please provide a screenshot of that app window and please hide any product key in the screenshot.