Odoo allows users to integrate SMS capabilities for various business uses through an IAP credits system. Key uses include contacting leads and clients, scheduling reminders, subscription alerts, and invoice follow-ups. Credits can be purchased in bulk and used to send SMS priced between €0.02-€0.13 each depending on destination. The number of remaining credits can be viewed in Settings and while the sending number is fixed, over 5,000 SMS can be sent with a €100 purchase of credits.