The broadcaster was tipped to take the driving seat on the flagship BBC show after Jeremy Clarkson was sacked for punching a producer in a row over steak.
When his appointment was announced, weeks after he ruled himself out of the running, the BBC also confirmed that James May and Richard Hammond would not be back.
Evans said that the audition was "not a stunt" and added: "We hope that that there's going to be an amazing response to this not just in the UK but around the world."
A candidate's video should demonstrate a "relationship with cars" and successful presenters will have to know "at least as much as or more than me" about cars, he said.
Wannabe presenters will then be whittled down for a live audition in front of Evans and the production team.
Evans warned they may not be picked to co-host the show, but may front a segment.
He said that there will definitely be a "female presence" on the show but not necessarily a co-host.
He said that the show was a "blank canvas ... but of course there are established features on the show that I don't want to see go as a fan of the programme, so they are not going anywhere.
"How much we are going to have to nip and tuck and shave and build upon we are not quite sure yet, but we are going to have a look, we are going to figure it out," he said.
"But one of the things, of course, we are looking for right now are co-hosts for the programme."
He said: "There will definitely be a female presence on the show, and that could well be a co-presenter, it could be two. It could be no co-presenters and a film reporter or a driver. It's all a big open book."
He added: "There is no guarantee that we are definitely going to have a member of the public hosting the show - it will only happen if that person is suitable and any good."
Anyone over the age of 16 with a love of cars is invited to audition.
- PA
