How I can get client to increase my partner level?

I’m new to Wix partner got 100 points for upgrading my one site. As a beginner how can I increase my partner level?

You need to become a contributor in other premium sites. You get 100 Points for every premium site you have in your account.
https://support.wix.com/en/article/wix-partner-program-levels

If I purchase premium sites for my clients can I get points?

Only if they add you as a contributor to their websites.

Do you mean I should purchase websites for myself only to get points? .Thanks, Fateh for your time.