Normally, a distinction is made between Scotch whiskey without an "e" on one side and Irish and American whiskey with an "ey" on the other.
However, there are now many other countries that produce whisky/whiskey. For example, Japanese, Taiwanese and Canadian whiskeys are spelled without an e - but there are exceptions to this as well.
Until the beginning of the 20th century, by the way, "whisky" was always written without an "e." But the Irish wanted to distinguish themselves from the whiskies of the Scottish distilleries. In the U.S., the "e" was also adopted, but again not consistently.
But the difference is not only the country of origin, but also the production or raw materials. Scotch whiskey uses malted barley, while Irish whiskey uses corn and other grains. In India, even molasses may be used.