Hi bigjimmyauk,
I assume you don't backup your O/S and therefore are not familiar with backup software?
if that's correct then I would recommend you get yourself whatever backup software you can, not just for migration of data but also to have a backup or two of your O/S working great before you install some dodgy software/drivers that mash up the place!
Macrium reflect as harry5522 suggested is meant to be good software but there are plenty others. I use Acronis True Image 2017 which is very good also. Depending what SSD you are buying you may get some backup/migration software include.
The actual process is quite easy with a couple of clicks and a progress bar for 15mins followed by a shut down so you can remove the old drive and perhaps a quick visit to the BIOS to configure the board to boot from your new M.2 drive.
If you current O/S is in good nick go for the clone but if its utter shambles maybe a fresh install would be the way to go?
