Hola Laith

In this context it's always "se", i.e. when it's used with impersonal sentences.

Se has lots of different functions. It is when the pronouns are used as indirect objects or reflexive pronouns that you use all of them. 

For example:

Me dio un regalo.

He gave me a present.

Le dio un regalo.

He gave him a present.

Me casé con Marta.

I married Marta.

Se casó con Marta.

He married Marta.

Saludos