You can't donate your entire Lyft fare to charity, but you can round up and donate the difference. Lyft partners with several charities including it's featured charity St. Jude Children's Research. Other partners include Black Girls Code, ACLU Foundation, World Wildlife Foundation, Human Rights Campaign and more.
To round up and donate, open the Lyft app on your device and tap your photo in the upper left hand corner. Tap Settings > Round Up & Donate then select the charity you wish to donate to. Finally, tap "Start Donating."To stop donating, tap "Stop" in the Round Up & Donate section.