YouTube Premium is the paid subscription offered by the YouTube to there viewers, with includes Premium features (discussed bellow) . It Gives Ad Free Experience Mainly ,Many of Premium users subscription due to This Future.
It can be purchased by Paying some Amount.
Features of YouTube Premium
1.) Ad Free Experience
There are no ads while viewing Videos. No Skipable ads, no In Video Ads, no In stream ads.
2.) Download and Go
This feature includes downloading video for lifetime.
For the normal user video downloaded for only 1 Month , but with Premium it is for Lifetime, And We Can download videos in 1080p Quality.
Watch Full Video on YouTube Premium here