If i have a rim hat is 1 inch across will i be able to fit a maxxis creepy crawler on it?
More importantly what is the diameter? Trials rims are know as 19inch, regular bikes use 20in wheels.
It really doesn’t matter how wide a rim is, but what the diameter is.
i just measured and diamiter of the rim from outside to outside was 16.5 inch but that doesnt seem right cause its for a 2oinch bike…
Chances are you got a beginner uni… go buy yourself and early birthday present and get a Nimbus Trials 
CC will fit on this no worries 
Sounds like you have a standard 20" rim. If you want to try using it for trials I would sudggest getting a 20" Onza Sticky Fingers
If your rim is only an inch wide that is also pretty skinny for any kind of high volume low pressure tire. The skinniest commonly used trials rim is 32mm wide. I think KH is 47mm. one inch is around 25mm
bike wheels are classified by approximate outside diameter. Add 1.95" (50mm) for a tire to either side of a rim just over 16" and you have around 20"
edit: and if you do get a trials rim go for something like the Monty Eagle Claw, CCs suck. I would rather ride a Luna (see trails tire thread by sponge)
Yah Kris Holm is 47mm, I would reccomend getting as wide a rim as possible as you tire will fold less.