Which one is correct why?
The salary range of this position is between 100k to 200k
or
The salary range for this position is between 100k to 200k
Either are correct, but "for" is more common
The salary range of this position.
Refers to the salary range belonging to the position. That is, what salary is tied to that post, which you would recieve if you took on the position.
The salary range for this position.
Refers to a salary that will be provided for working in that position. Potentially, it associates the salary with working on the position and not arbitrarily with the role itself - but for all practicality there is no difference in meaning, and there is definitely not a difference that would be noted by anybody hearing this phrase.
In general, using "for" is more common (perhaps as the general association is being paid for actually performing the work, although that is speculation).
But as mentioned - there is no practical difference between these phrases, and no native speakers will be taken off-guard by using one over another.
side note: Google ngrams, showing the general preference to use "for" over "of"
The salary range for this position is between 100k to 200k. You must use "for" when you talk about this because you want some information about the position at work, can't use the genitive
example in the sentence: You can ask "What is the salary range for this position?" when a recruiter first contacts you about a position.