Apply Mesh

This operator applies all the modifiers in the active object and can also convert curves to meshes which useful for operators like Random Tubes and Random Cables.

Figure 1

It can also work on multiple selected objects.

Figure 2

If you wish to only apply the mirror modifier on the selected object(s), hold the Ctrl hotkey while clicking on the operator button.

Figure 3

In Figure 3, the active mesh has a mirror and a bevel modifier. With the hotkey combination mentioned above, only the mirror modifier was applied leaving the rest of the modifiers intact.