The letter heh can sometimes be used at the end of a word to show that the previous consonant has a vowel after it, usually a vowel with an “uh, “ah”, or “eh” sound.
The letter alef can be used the same way, but is not limited to the end of a word.
The letter vav can be used for the same purpose, but to indicate “oo” or “oh” vowels more specifically.
The letter yod can also be used for the same purpose, but to represent “ey” or “ee” vowels more specifically.