Details on their api would be required for a start.
There are lots of examples on intergrations.
Some simple message servers you can use a url printer that uses a printer template and print job. A more complex api may required but more work in creating a.script to post auth and message content to their api.
https://api-mapper.clicksend.com/http/v2/send.php?method=http&username=username@useremail.com&key=yourapikeygoeshere=$number$&message=$message$&senderid=customphonenumber here if purchased
number={ENTITY DATA:Deliverers:Phone}
message=Hello {ENTITY DATA:Online Customers:FirstName} [=F(TN('{ENTITY DATA:Online Customers:Phone}'),'# (###) ###-####')] has placed an order for Delivery. Here is the address: {ENTITY DATA:Online Customers:Address}
number={ENTITY DATA:Online Customer:Phone}
message=(AUTOMATED FOOD DELIVERY MESSAGE) Hello {ENTITY DATA:Online Customers:FirstName} your food is on the way. {ENTITY NAME:Deliverers} will be arriving at your door shortly. Thank you, Moore's Dairy Creme. Please do not reply to this message as it is automated. Call 870-799-3980 if you need assistance with the delivery.
You set a print job for it and then use a rule and action to decide when to execute them. In my case I used delivery setup and when a driver was assigned to the ticket it executed both print jobs sending a text to driver and a text to customer.
Look in the url, the username, password, number and message are part of it thats how they know who you are and who your messaging.
The number and message are variables from the print templatr