tense for past job experience?

When talking about a past job experience, can we use present perfect tense?

For example; "after I started working for x co., i have had experiences on ... (I want to emphasize that i stil have these qualifications, but I am not working for that x company now. Or should I use past tense?

The present perfect means that you are choosing to present the events as having some present relevance: the exact meaning of that relevance is variable.

I have had experience on ... generally means that your experiences are over a period that includes the present.

A likely interpretation is that you are still in the relevant job:

Since I joined XYZ, I have had experience on ...

sets up a strong presumption that you are still there.

However, you could be using it over your career (a period that includes the present). If so you would need to choose words to make it clear that you were not referring to a single job, eg

From the time I was at XYZ, and subsequently, I have had experience on ...

But if you are talking about experience at a job that is in the past, the past simple is much more natural.