Vocal Doubler is a new plugin from iZotope that, as its name suggests, is designed to add a doubling effect to your vocals. It can be used when you want a richer tone and more depth. The interactive interface should make it very easy to dial-in the effect. Simply drag up and down to increase and decrease the stereo separation, and pull left and right for natural ‘human-like’ variation.

Used on individual tracks, the Vocal Doubler can add a sense of space to make them stand out in the mix, while Effect Only mode enables you to create multiple doubled vocals on different tracks. Vocal Doubler is perfect for placing directly on your vocal track and just adding a touch of space to make it stand out in the mix. Using "Effect Only" mode, you can also create multiple doubled vocals on different tracks to further customize your sound.

 

More info - https://www.izotope.com