Here's a step by step for Twilio so that you can send automated text message reminders and receipts to customers: 

Here's a good Knowledge Article for setting up automation - How to set up automation: Email/Text Reminders and Receipts

Twilio Integration: 

1. Create a Twilio account
2. Create a Twilio number by clicking on "Buy a Number" in the top right corner
3. At creation - make sure that the number has SMS enabled capabilities
4. Go to Twilio's Dashboard page
5. Copy the Account SID and Auth Token (click on "Show" then copy)
   
   

6. Inside of MMIO got to Settings -> Integrations - Text Message Gateway - Twilio 

7. Click on "Connect" 

8. Enter your Twilio phone number - please include the +1 in front of it: +16784690290 

9. Copy the Account SID and Auth Token into the corresponding fields

10. Click 'Save'

Need help on integrating Twilio? We can help - 24/7: hello@modernmaid.io