I searched all already asked questions here on Stack Overflow, and all of them deal with “sending” an SMS programmatically to another phone and that is NOT what I want.
I want to just add an SMS to the inbox, without using the cellular network or any other service and write a from “my_company_name” etc. Basically I want to avoid making the user or my company pay for the SMS. I know about push notifications and I will use them as well, but I need SMSs.
I thought about that maybe, if the user sends the SMS to himself it would be free of charge, but that “seems” to be not true at all.
The Messages app (and its notification UIs) only displays messages that come in over SMS or iMessage. What you’re looking for isn’t possible with public API.