Electronic authorisation is not the same as a traditional visa
An electronic travel authorisation is commonly a pre-travel permission for travellers who are otherwise visa-exempt for the covered trip. The United Kingdom, for example, says some travellers may need either a visa or an electronic travel authorisation depending on nationality.
The exact eligibility, validity period and permitted activities are destination-specific, so the label alone is not enough.
An eVisa is still a visa process
An eVisa usually means the application and/or visa issuance happens electronically rather than through a physical sticker process. Requirements can still include documents, fees, processing time and a specific permitted purpose.
EntryAtlas treats eVisa as an electronic-access category for discovery, then points travellers toward the destination authority for the real application rule.
Visa on arrival moves the permission step to the border
Visa on arrival generally means the traveller does not need the visa issued before departure, but conditions can still apply at the arrival point. Airline boarding rules, accepted ports of entry, fees, photographs or supporting evidence may matter.
Do not assume the phrase means every border crossing offers the same facility.