Almost certainly, however, SLI is not available on all motherboards.
In most Skylake boards that support SLI you will have two PCIe x16 slots connected directly to the CPU. These will support 16x/0x and 8x/8x configurations. The remaining slots in your PC run through the PCH and communicate to the CPU via DMI. Depending on the chipset, that can be up to another 24 PCIe lanes.