Move a hard drive from a mac book 2012 mid to a Mac Pro mid 2012
Sure you can - it will even boot from it if you ask it to by holding Opt at the chimes.

Your only issue may be to get it to physically fit the drive sled in the Pro. For that just get a physical adaptor so that the connectors line up properly.

OWC are well-known for their Mac-compatible products - selection of their drive adaptors. Make sure the one you get is for a 2012 Mac. I'm not certain if the adaptors need to be different [they probably don't, you just need a 2.5" to 3.5" adaptor, cheapest, first in the list] but I do know that the earlier Mac Pros had very very slightly different sled designs. Really hard to tell by eye, but they are not swappable.
I have two early Pros &amp; two late Pros… &amp; the number of times I've tried to use the wrong sled… D'oh!
I have one of their adaptors on a 3,1 but I've never actually tried it in a 5,1. It came with the machine so I never had to spec it myself.  My 5,1s I actually have SSDs mounted into the optical bay, which needs a slightly different adaptor type, 2.5 to 5.25, as opposed to 2.5 to 3.5.