There are many things this could be. The most simple checks to make are:

Jack the car up one corner at a time, get a axle stand underneath so you don’t crush your self, and give the wheel a shake from left to right. Then again from top to bottom.

If this doesn’t create the same noise, then a good common area to look is the springs. Are any of them broken or cracked? the spring can still function and the car can still drive fine, but a broken section of spring may just be rattling in its position.

Failing this, you will need to get it on a ramp and have a good pull and a prod at all of the suspension arms and struts.

Let me know how you get on.