Be careful with that workflow. If you ever share the modified PDF that rectangle likely hasn't redacted anything.
On a digital PDF the underlying text is still accessible, and even if the PDF was a scan, the original image likely hasn't been modified, instead a new shape layer was added.
I usually end up printing out the dead-tree version with the black rectangles, and scanning it back in, just to be sure the data under the black rectangles can't be retrieved.
1. Set Shape Fill color
2. Set Shape Border color
3. Insert a Rectangle.
The rectangle can then be moved/resized/copy/pasted to cover names precisely and won't inadvertently leak names like the spraypaint tool does.