A USB 3 to M.2 Reference Design Schematic
Assuming that you are trying to interface to an NVMe M.2 SSD, what you are looking for is called a USB3 to NVMe/PCIe bridge (If your M.2 was instead SATA, for example, you would be looking for a USB3 to SATA bridge).

Two USB3.1 Gen 2 to NVMe bridges that I know of are the ASMedia ASM2362 and the JMicron JMS583.