These are all standard Apple menu items.

Services has no relevance to RealCADD.

Hide RealCADD (keyboard shortcut ⌘H) simply hides (but does not close) the RealCADD windows that are open.

Hide Others (keyboard shortcut ⇧⌘H) simply hides (but does not close) all open windows except RealCADD.

Show All shows (and un-hides) all open windows.