What is an slot on a motherboard used for?

Will a M+B key 8x Sata card work in a M key socket? m 2 card slot An M2 PCIe SSD solid state drive storage slot on a motherboard slot for the video card with purple illumination Socket am4 Building a m2 sata slot Discover the benefits of our expansion card slot dual SSD and dual PCIe adapter PCIe expansion card for lightning-fast speeds Shop Now!

m2 slot card in their WWAN card slot The On the contrary, the L-series among others can only support cards using the PCIe standard in the WWAN slot