I heard today in my Japanese class my sensei pronouncing ひと the "ひ" like し my teacher is not from a Japanese origin he studied there. I want to know is this pronunciation right? Should I pronounce every ひ as し? Or ひと is the only case?
Neither, really. Merging し and ひ happens in certain dialects, and your teacher probably studied somewhere where that merger is common. You can choose to do it this way, or you can choose to not.
(It has nothing to do with the individual word ひと, though. Some people might merge し and ひ in some places and not others, and before a /t/ might be one of those places, but it's not a single-word phenomenon.)
The 「ひ」 in 「ひと」 is usually pronounced as kind of a silent huff of air.
Similar to how 「し」 is pronounced as a silent sound in 「している」 (like saying "sh-teiru).
Or how 「つ」 is a silent sound in a word like 「みつけた」. (like saying the 'ts' sound without sounding out the 'u' in 'tsu').
But pronouncing these as 'silent sounds' is only for certain words. There are definitely plenty of other vocabulary where these are fully sounded out.
I hope that helps somewhat! *^_^*