The starting markets are the United Kingdom, France and the Netherlands.
According to the press release, the future BEVs from Hyundai (like the upcoming Ioniq 5) might also be offered at some point.
Another area of partnership might be education and promotion:
"In the future, Hyundai and Uber intend to launch joint marketing and education plans to promote electric cars and their associated benefits to Uber’s partner drivers, as well as to offer test drives to allow drivers to experience zero-emissions vehicles first-hand."
Uber plans to become a zero-emission mobility platform by 2030. By 2025, 50% of the mileage in top European capitals, responsible for 80% of the Uber’s European business, to be zero-emission. That would mean 40% of the total business to be electric within 5 years from now.
"The agreement between the companies was revealed based on Uber’s announcement that it plans to become a zero-emission mobility platform by 2030. By 2025, 50 per cent of the total aggregated kilometres of Uber rides across seven European capitals will be driven by electric vehicles. These cities (Amsterdam, Berlin, Brussels, Lisbon, London, Madrid, and Paris) will make up 80 per cent of Uber’s European business by the end of 2021. As part of this pledge, customers will be able to select the option of riding in a zero-emission vehicle when booking their trip."