LONDON—This city’s decision to revoke Uber Technologies Inc.’s operating license opens a window into what drivers say has been a relatively common practice of sharing or renting out driver accounts at a number of ride-hailing apps.

Transport for London, the city’s main transportation regulator, said earlier this week it determined 14,000 Uber rides in late 2018 and early 2019 weren’t conducted by authorized drivers, but by others who had been able to substitute their photos to use a real driver’s account.

Several...