JOcean is correct. spec for storage says: Up to 512 GB you can still install your M.2 sata ssd in this pc though not at the M.2 slot.  you can use a PCIe adapter that supports m.2 sata ssd such as this one on amazon.
In an attempt to speed up my Dell Inspiron 3670 PC, I have installed a V-NAND SSD (500GB 860 EVO SATA  by Samsung) in the M2 slot on the motherboard. However, on powering up, the new SSD is not recognised by the system. It is not showing in Windows and I have checked the BIOS on start-up and the M2 slot is shown as being empty. There is a lot of differing and highly technical advice on the internet about changing settings in the BIOS, which I am reluctant to try in case I do serious harm to my set up. Can anyone help please. The specification for the motherboard M.2 slot is Type: 2280 Solid-State Drive (SSD), Interface: PCIe 3 x4 NVME, Capacity: Up to 32 Gbps Up to 512 GB Thanks
M2 SSD not recognised by BIOS