When copying an existing object by selecting the object and then “Copy” from the right-click menu (shortcut Ctrl+C) you can create a standalone copy of the object by right-clicking on the model area and select “Paste as copy” (shortcut Ctrl+Shift+V). The new object will have the text “(Copy)” appended to the title.
If you instead choose “Paste” (shortcut Ctrl+V) you will reuse the existing object and a new symbol1 referring to the same object will be created.
1 Objects are the underlying entities that have properties like title, description text, and connected documents. Symbols are the graphical representations of objects that are visible in the model area and have properties like color and size. When you copy an object the regular way (Ctrl+C followed by Ctrl+V) you create a new symbol referring to the same object. The new symbol can have its own color and size, but the title and description text will always come from the underlying object. The reuse of objects is one of the strengths of 2c8 Apps compared to less advanced drawing tools but it can be a bit confusing if you are not aware of how it works.