How do I mirror multiple objects in blender?

How do you use the mirror modifier in blender?

Applying the modifier is easy:

1. In Object Mode, select the mesh.
2. In the Editor on the right side, find the Modifiers tab.
3. Click the Add Modifier drop-down menu and select “Mirror”.

How do I mirror an object in blender without modifier?

This works both in Object and in Edit mode. Press Ctrl+M (or find command Object->Mirror Mesh->Mirror) and then select the axis you want to mirror the duplicated object along (in interactive mode press X, Y or Z on the keyboard). Click left mouse button to confirm.