Fiverr is a global company, from the first paragraph of the Terms of Service it's primary company is from Israel: "The following terms of service (these "Terms of Service"), govern your access to and use of the Fiverr website and mobile application, including any content, functionality and services offered on or through www.fiverr.com or the Fiverr mobile application (the "Site") by Fiverr International Ltd. (8 Kaplan St. Tel Aviv 6473409, Israel) and its subsidiaries: Fiverr Inc. (38 Greene St. NY 10013, NY, USA) and Fiverr Limited (Lemesou 11, 2112 Nicosia, Cyprus), as applicable. Fiverr International Ltd. and its subsidiaries are collectively referred hereto as "Fiverr" "we" or "us" and “you” or “user” means you as an user of the Site."
Also, yes they take 20% of tips, Fiverr makes more money when Buyers transfer more money on their platform, regardless of the reason of money transfer.
You can read more about tips on Fiverr here: https://www.fiverr.com/support/articles/360011454477-Buyer-FAQs?segment=buyer