In addition to being able to send requests via email, you can also send them via WhatsApp and SMS.  

The pricing of SMS and WhatsApp is not always straightforward, and this article aims to make it more easier to understand.

The SMS / WhatsApp usage fee is added to your monthly invoice and the phone number (usually around 1-2$ USD / month) is included in the usage fee.

SMS pricing

The cost of an SMS message is calculated by multipliing the the number of segments used by the price per segment (which depends on the country of destination). The number of segments depends on the length of the message and the characters used.  Here's an article about segments. You can also calculate the number of segments using this tool. 

For exemple, an average message to a customer might about 0,15$USD (0,073 x 2 segments) for a customer in Switzerland and less than 0,02$ for a customer in Canada (0,0079 x 2 segments).

WhatsApp pricing

WhatsApp messages are billed based on the number of conversations and the destination country. Pricing is available here. An additional fee of $0.015 USD applies when messages are scheduled (most of your messages will be scheduled).