The Oort Cloud begins about 2,000 to 5,000 AU from the Sun and stretches to about 10,000 to 100,000 AU (0.16 to 1.6 light-years), according to NASA. But keep in mind this outer boundary is pretty nebulous, so there is no hard line where the Oort Cloud ends.
The comet, C/2014 UN271 (Bernardinelli-Bernstein), is over 128.7 kilometers in diameter and has a mass of around 500 trillion tons. It won't hit us, but it will help us understand the Oort Cloud.