First you will want to make sure you have a vehicle that is in good running condition, and that you meet their driver requirements. You must be at least 21 years old and have a US drivers license. For Lyft you must have 1 year driving experience, and Uber you must have 3 years driving experience.
For Uber the age of the vehicle must be a 2002 or newer. For Lyft your vehicle must be a 2006 or newer. Both companies require 4 passenger seats. The vehicle must be licensed in the state and have up to date tags and registration.
There are online applications for both Uber and Lyft where you must fill out and agree to background check information. Background checks can take from 3-14 business days to complete.
Once you have passed the background check you will be notified to proceed with the vehicle inspection. To prepare for this you will want to make sure your vehicle has been cleaned and maintained. After you pass the inspection you will be able to drive for their company.