I cannot get any of the high res mods to work and the voodoo2 graphic utility doesn't work either. I have the grayface mod installed but all I get is mouse looks thats it. Nvidia Control panel doesn't affect anything graphically with M&M 6 at all is it because it is too old?

There really isn't a huge difference with the HD Textures Mod. This post does go over how to install it though:
https://www.gog.com/forum/might_and_magic_series/how_to_apply_greyfaces_hd_textures_mm6/post3

As MM6 uses a software not hardware based engine, you won't get many improvements from playing with your GPU settings. You CAN use a wrapper like dgVoodoo2 if SupportTrueColor is disabled (SupportTrueColor=0) in the mm6.ini (Not necessarily better). Or if you have MM8, you can use the merge patch and run MM8 in hardware mode, but that changes the vanilla MM6 experience significantly and there's still some issues with it.

Additionally, If you do decide to use dgvoodoo2 make sure you have the files from the zips "MS\x86" folder in your root MM6 directory.

Really, my suggestion would be to install the HD textures IF it interests you and just play the game normally. I personally like using mouselook and re-encoding the music mp3s to wav and then setting "MusicLoopsCount=0" so that you get continuous music as well. (The re-encoding to .wav may not be necessary depending on your system)

Thank you the watermark shows up when the game starts up so I know its working but I get 2 side by side green screens I don't think MM6 likes it. The HD mod loads up at the start and takes a while at the second start of M&M 6 when starting up like it should but I don't see a difference.

Just tested it on my end with dgVoodoo2 and like you I initially got the 2 green screens.
Fix for me is to additionally set "BorderlessFullscreen=0" in the mm6.ini
Do check and see what look you prefer between Grayface's modded MM6 engine (SupportTrueColor=1 and
BorderlessFullscreen=1) or the dgVoodoo modified vanilla MM6 output.

And yes, the difference is slight with the HD textures. Look at the pattern of the paving stones in New Sorpigal to see one of the most noticeable difference. Some may even prefer the original look VS the upscaled.

A very convenient option is to use the Greyface patch. It will run the game at your desktop resolution if specifically selected.

It is much more visible and noticeable in Might and Magic 7 and 8, letting you run the game in a real widescreen mode with a tweaked UI to fit the new mode.

If that patch is used yo can get rid of any dgvoodoo2 or similar. The patch also makes the game compatible and stable with newer windows and no compatibility or external tweak is needed to have a stable and smooth gameplay.