Experience can be used as an uncountable noun. You use it when you're talking about knowledge or skill which is obtained from doing, seeing or feeling things.
For example: Do you have any experience of working internationally?
Experiences is a plural noun, and when you use it in this form you are talking about a particular incident or incidents that have affected you.
For example: It was interesting hearing about his experiences during the war.
Experience can also be a verb. It means something that happens to you, or something you feel.
For example: Many people experience a sense of dread when they think about exams.
Thanks to Ngoc Khanh