I read this phrase from a book today but i cannot fully understand what does it mean
is it like "it is a driving forece in the the entrance of success"?= a key/an avenue/a read/the prerequisite/precondition to success?

sue, I can't tell, without more context. If it's something like, "His access to a lot of money was a driving force in his entrance into politics", then your idea of "key" would apply: easy money was a key force, we might say. If it was something like, "Good grades are a driving force in the entrance into a top university", then it would be seen as more of a prerequisite.
I realize there is not much actual differentiation here. The best explanation I can offer for my two examples is that, in the first instance, we are left thinking that perhaps if the candidate had NOT had a lot of money, he might not have chosen to go into politics.

If "success" is actually® the proceeding word, it may be similar to "A best practice in initiating a result-driven game plan" [self yart-e]

A driving force is the cause of someone's working toward a desired result.

"His need for money to pay bills was the driving force (behind) his working hard to accumulate wealth."

"Her love of knowledge was the driving force (behind) her pursuit of multiple academic degrees."

""it is a driving forece in the the entrance of success"
Dear SD: I think the big problem is that phase is the word "entrance". Success comes mostly
to the people who work hard to "achieve" it. Hard work is the principal driving force in the
achievement of success.