A medical visa is separate from a tourist visa, and applying on the wrong category is one of the most common reasons a treatment plan gets delayed.
What you generally need
Applications usually require a passport valid well beyond your intended stay, a letter from the treating hospital in India, supporting medical records or a diagnosis from your local doctor, and evidence that you can meet the cost of treatment and stay.
Attendants
Most medical visa categories allow accompanying attendants, typically close family members, applying under a linked category. Confirm the current limit and relationship rules before booking travel for anyone else.
Timelines
Processing times vary considerably by country and season. Begin the process as early as your hospital letter allows, and avoid booking non-refundable flights until your visa is issued.
Visa rules change. Always confirm current requirements with the Indian mission in your country before applying.