In French, there are TWO subject pronouns (i.e. I, you, he, etc.) to express we : nous and on.
Look at these sentences using these pronouns:
On is a more informal we, used predominantly in speech or casual writing (in emails to your friends for example). This is also a singular pronoun which is followed by the same form of the verb as singular il or elle.
You can see it as an equivalent to the English 'one' in form, if not exactly in meaning.
See also On = we, one, people