It depends how these tips were reported to you. Generally, you would report this type of income under Other Common Income (if you received Form 1099-NEC or 1099-MISC) or Miscellaneous Income (if you kept your own records).
The easiest way to find any section of TurboTax is to open your return and use the Search box at the top right side of the TurboTax header. Click on the magnifying glass, type in the form you need, hit Enter, and click the "jump to" link to go directly to beginning of that topic.
Or go to the left column in TurboTax Online and click on Tax Tools >> Tools >> Topic Search. Type in your topic, then click the topic in the list to go directly to the start of that section.