How do I make the cursor be at the object?

[bluberry (T)]

I have this ring but the cursor is not on the object. How do I get the cursor to be at the middle of the ring?

[Okidoki]

Top right: enable Options: Origins and move it… do not forget to disable it afterwards…

[Meshmonkey]

Rightclick → origin to geometry

[Matakani]

Right Click > Snap > Cursor to Selected.
Or use Shift-S > Snap > Cursor to Selected.

But it looks like you actually want the Origin at the Object, which is what @Meshmonkey told you how to do.

This is basic stuff. Read the Manual and watch some beginner tutorials. Both are available in Blenders Help Menu.