Question about AMD Ryzen 7 3700X

Yes you can, this type of sale is called a "tray" for CPUs. So it's really just the CPU without any packaging from the manufacturer.
But it doesn't make sense for private individuals to buy them individually because they are usually even more expensive. It only makes sense if large quantities are bought (quantity discount), e.g. for companies that assemble PCs.

AMD Ryzen 7 3700X (AM4, 3.60GHz, 8-Core)