Reactor -- Drop a Cloth

Make a box and while it is selected, hit Rigid Body Collection. Keep the default properties of no mass so the box stays in place.

Make a cloth right over the box. This shows a plane with 8 segments.

While it is selected, hit the Cloth collection button.

Preview, and you will see self-intersections:

Select Avoid Intersections for a better result:

You could also use a box for cloth with a very slight height [segment of 1], but you will definitely need to select Avoid Intersections:

Tip—use Update Max to create a non-animated model of draped cloth:

This is in the Preview Window:

You have to close the preview window to see the result:

If you want, you could Save As +, then collapse the stack and add a meshsmooth: