I want to make the smoke particle have infinite duration. It has 5.00 by default.

What can I do.

Unless I’m mistaken, if you simply check looping (located under duration) then it will go on forever.

As stated here: Unity - Manual: Main module

You need to click on it, and then you can change it by making it have more particles. You might have to browse a little bit though before you can figure out exactly where it is. You might also try toggling the gravity of the particles