Shipt Shoppers are considered independent contractors meaning you are responsible for withholding your own taxes.
If you earn over $600 from Shipt over the course of the year, they will send you a 1099 form which is what you use when filing your taxes. Even if you don’t make that much with Shipt, you are still responsible for reporting your earnings.
Here’s a good article to understand how taxes work for side hustlers: How to Handle Taxes
for Your Side Hustle.