All travellers arriving in India are legally required to have a valid visa (except Maldivian nationals).
Eligible citizens travelling for tourism, yoga, business, medical or to visit acquaintances have the option of applying for an India visa online which is granted electronically. When the Indian government implemented this new electronic process, it called it Electronic Travel Authorization (ETA). As the visa stamp is placed inside the traveller's passport at the airport on arrival in India, the application form is also called 'Visa on Arrival'. This could be confusing for travellers; it is very important to understand that the visa must be applied for and approved prior to travelling to India, or you may be denied boarding or disembarkation.
The official name of this process then changed to "e-Tourist Visa (eTV)" and then "e-Visa" in 2017. The online process has not changed, biometric information of the traveller will still be taken at the airport and stamped inside the passport upon arrival in India.