This sentence is present tense. Is used is an action verb, but in the passive voice.
It does. It, too, is passive voice. Usually, we write setences "subject + verb +complement," with the complement receiving the action from the verb (active voice). In passive voice, however, the subject receives the action from the verb. In the sentence you gave, it's either not important or not known who is actually using the button. Otherwise, it's better not to use passive voice.What I want to tell is "this button can be use to export...." Does the above sentence give that meaning?