Well, I suppose your native language does not have this sound, a uvular fricative the Hebrew ר has taken from central European area strechting from France to Germany, Danmark to Yiddish. Your ear has to adapt. For me, using this sound all the days of life, it is clearly there and audible.
I wrote in Hebrew:
"קוף רואה קוףה"
(A monkey sees a [female] monkey)
I passed but I got a spelling correction:
I don't remember off the top of my head but there are some Hebrew letters that have two forms. One form happens if they are before the last letter of a word and the last ending of the letter. Right now, I am thinking of the letters:
Is this the reason why my spelling was corrected? What are the letters that behave in this fashion?
Writing קוףה is indeed incorrect. There are five sofit (final) letters, that appear only at the end of the word (not sure where you have the "before the last letter of the word" part from).
regular kaf כ, kaf sofit ך
regular mem מ, mem sofit ם
regular nun נ, nun sofit ן
regular pey פ, pey sofit ף
regular tzadi צ, tzadi sofit ץ