Why there is darkline in my screen i realy hate this.urgent reply needed??

My S7 edge was bought only on june of first week,till yesterday everything seems perfect but now i see darkline in my screen i.e 3 line crossing my screen. would you please tell me or suggest how to remove this things.

You can't, since it's either a bad screen, a bad connection from the screen to the motherboard or a bad part on the motherboard. It has to go into a shop for repair. (It's still under warranty, so you shouldn't have any problem.)