Can Mid 2012 Macbook pro be upgraded using nvme ssd using an adapter
There are M.2 PCIe to SATA adaptors that you could use, but there are two problems: Firstly, you're not going to see the faster speed of the NVM RAM, because the SATA interface is the bottleneck, and won't go any faster than 6 Gbps.
Secondly, ensuring that the adaptor card and the new SSD module will all fit together inside your laptop: neither being too big, nor rattling around loose.

The simplest thing is to replace the existing mechanical hard drive with a 2.5" SATA SSD. This will slot in exactly in place of your old drive, and will cost less than an NVM RAM module.

(Links to UK stores.)