You do not move it, You un-install it from the C drive and then you see it its installer has any option to install it onto some other drive. If does some Photoshop stuff will still be put on the c drive like ACR cache your preferences etc. You can not simple move it. There are too many registry setting pointing to its C location.. .
You should actually get a free utility like WinDirStat to see what's big and eating up you C. See if any big stuff you see can be eliminated or moved. For example if you have GB of ram and do not hibinate your system. If Hibernate is turn on there is a RAM size hibernation file on the C disk. Turning of hibernation support will delete that file and you will regain GBs of space on your C:
If you're already running out of space on your boot drive, the relatively paltry amount of room you'll gain by moving Photoshop to a different drive won't even begin to make a dent in the issue.
Get a new, much larger drive.