Usage of the Impersonal Pronoun On
The pronoun on is used in several situations:
Rule 1: to describe general facts.
French
English
On dit que le soleil est jaune.
It is said that the sun is yellow.
Rule 2: to describe a situation in which the subject of the sentence is not known or deliberately not identified. We could use "someone" here.
French
English
On m’a volé mon portable.
Someone stole my phone.
Rule 3: in spoken French, it’s often used instead of "we."
French
English
On part !
We’re leaving!
Watch Out!
While the pronoun on is impersonal, it does replace the person or action made by the person. It can't be used instead of "it."