Your 1099-K reports earnings from third-party transactions (in this case, from riders to drivers). Earnings are calculated from fares, tolls, city fees, airport fees, split fare fees, and booking fees.
The booking fee is a separate flat fee added to every trip that helps support safety initiatives for riders and drivers as well as other operational costs.
Note: not all states have a Booking Fee. If you drive in California, riders are instead charged a Marketplace Fee directly.
To understand if the booking fee is deductible in your situation, it is recommended you contact an independent tax professional.