In India we need to provide visa details and air tickets to get an International Driving Permit (IDP). If I am traveling to multiple countries, do I have to apply multiple times or is a single document enough for all the countries which accept IDP?
There are 3 slightly different versions of the International Driving Permit: the 1926 Convention, the 1949 Geneva Convention, and the 1968 Vienna Convention. See https://en.wikipedia.org/wiki/International_Driving_Permit for details. You might find you need to apply for 2 permits. Which one(s) you need is dependant on which convention your destination countries have ratified.
You do not need to apply multiple times.
The original question was if you need an international driving license per trip. This should not be necessary. As noted, there are international conventions for international driving licenses.
Nothing in those conventions says that a license would be limited for a single trip or country. The license is valid until its expiry date.
However, the overall picture is a bit more complicated:
- There are different types of conventions and IDLs
- Not all countries accept all types
- Most countries only issue one type
- Example: Germany does issue IDLs according to the Vienna convention, but Japan requires one according to the Geneva convention: A German in Japan cannot use their IDL, but has to follow a different procedure
- IDLs are not always required between all countries
- Example: EU driving licenses are always valid in all EU countries and some more
- IDLs may be required in theory, but not in practice
- Example: Europeans in the US theoretically need an IDL (at least in some states), but in practice nobody will ever ask for it.
Usually any travel guide (or your national automobile club) will know what the rules are for that country.