The imperative is used to give orders, instructions, advice, warnings, offers, and requests.
Evacuate the area immediately.
Stay calm during the emergency.
Negative (using Don't / Do not + base verb):
Don’t touch fallen power lines.
Do not ignore official alerts.
Note:
We often use the word please at the beginning or end of a sentence, separated by commas.
Please, stay indoors during the hurricane.
Stay indoors, please.