M.2 vs. NVMe: What is the difference when it comes to SSDs?

nvm slotNVMe was desned for SSDs and communicates between the storage interface and the system’s CPU using hh-speed PCIe sockets without the limitations of form factor. The NVMe protocolI bought a new PC with 2 nvme slots and I bought a new SSD for it but it didn't come with a screw. It's a B560 DS3H AC motherboard.