I bought a new vanity for my bathroom the drain is about 4 inches off is there a flexable line I can use to make up for it being off?

You just swing the trap to the side... or use 45 degree or 22 1/2 degree fitting to point old drain towards new location.

Is that existing drain plastic or metal ?

Hi guys...

Karen, there is indeed a flexible line (see image), but it will not make up for a 4" offset... not for a bathroom sink drain.

Most likely, as Milo pointed out you will need to swing the trap or cut the drain and redirect it using the correct fittings.

Answer Milo's question(s) so we know more...

Mark