When an action performed by the doer only affects himself/herself, the verb is called an intransitive verb. In the sentence, “Tom sang a song,” sang is an intransitive verb because Tom and no one else is singing a song.
Let’s use the verb “to come” (आ) as an example.
I came (masculine) – मैं आया
I came (feminine) – मैं आई
We came (masculine) – हम आए
We came (feminine) – हम आईं
You came (masculine) – आप आए
You came (feminine) – आप आईं
You all came (masculine) – आप आए
You all came (feminine) – आप आईं
He came – वह आया
She came – वह आई
They came (masculine) – वे आए
They came (feminine) – वे आईं