Whoever is talking you that via "word of mouth" doesn't know how big gig work tech companies work. Also, not tracking mileage results in higher taxes, not lower.
FAT SEXY said:
There is no cash under the table with Uber, Lyft and Doordash. It's all in the app.
They will send you a 1099 with your earnings already tallied, it's up to you to file.