Before using this feature, make sure to enable the option to send SMS from order by following this tutorial : http://bit.ly/2JU8pnU.
If you have already done it, you can continue the process.
The first field Phone Number is the one where you have to put the phone number of your customer that you want to notify.
The second field : “Your message that needs to be sent here.” is the one where you will put the message to send to customer.
Get default messages : allowing you to retrieve the default message to send to your customer, he is the one that you have define here.
Send : allowing you to send the SMS.
After sending, you will have a report that will be added to the notes of your order and that includes the details of sending SMS.
Here is one example of WooCommerce orders notes :
Relatives: Before sending a message, always make sure you used the correct country code for your customer.