Toe-walking is a benign symptom of autism. Autistic people may sometimes or often walk on their toes.
Mayo Clinic does not recommend seeking treatment for autism-related toe-walking. Therapists' efforts would be better spent on issues affecting quality of life (e.g. communication issues or motor skills). If the autistic person falls often, occupational therapy may be helpful for improving balance.
While it is usually harmless, toe-walking should be mentioned to a doctor, because sometimes it is caused by underlying conditions such as a short Achilles tendon, muscular dystrophy, or cerebral palsy.
If an autistic person is toe-walking because of uncomfortable textures on the floor (e.g. a dirty floor), then they may benefit from wearing socks, slippers, or shoes indoors.