Good morning, @krystina.
I've got you covered. I can give you some insight into categorizing a tip for an external person/vendor.
@Rustlerdoes have some very good information that can help you decide what might be more accurate. However, I do recommend consulting with your accountant to be sure. They'll be able to give you the best accounting advice for your business. If you don't have an accountant, check out this link to find one near you.
In addition, here's a guide that could be beneficial for you: Share tips.
Let me know how it goes and if you get a definite answer from your accountant. Being able to categorize this correctly will ensure that your books are accurate. Should you need any further assistance, don't hesitate to ask. The Community is always here to have your back!