The imperative or “l’impératif” is a verb mood that is used to give orders, make requests, suggest an idea, give directions or offer advice. 
Get out right now. I don’t want to see you.
Prépare-moi un sandwich.
Fix me a sandwich.
 
Please, contact your provider as soon as possible.
Giving orders:
Sortez tout de suite. Je ne veux plus vous voir.Get out right now. I don’t want to see you.
Prépare-moi un sandwich.
Fix me a sandwich.
Making requests:
Veuillez contacter votre fournisseur le plus tôt possible.Please, contact your provider as soon as possible.