How to use wide angle lense?

Hi, i have a nikon d90. What kind of lense do you attach the wide ange adapter to?

Firstly, what is a wide angle adapter?

wide angle lenses are usually any that are under 18mm focal length (Tamron 10-24 or Sigma 10-20)

but you sound like you have something that is added to an existing lens to "simulate" a wide angle lens… So they are usually poor quality and ruin photos…

I agree with the other guy^^. I had one of those attachment SUPER wide angle lens. Lol and it made them look like complete trash! It cuts off the part of the photo, the top corners are blurry. If you want a real wide angle like I'm about to get soon, look on B&H photography. They have real wide angle for cheap. Look at like 10-24mm sigma or 11-20 even 14mm. Anything under the 18mm focal length is wide and the lower you get it's wider then eventually turns to fisheye.