Hi
I think you are looking out for how to interface GSM module with microcontroller, if yes then check out these projects:
1.with Arduino https://www.engineersgarage.com/embedded/arduino/how-send-message-gsm-module-using-arduino
2. with AtMega32 https://www.engineersgarage.com/contribution/how-to-interface-GSM-SIM-300-modem-with-atmega32-to-send-and-receive-SMS
3. with 8051 https://www.engineersgarage.com/microcontroller/8051projects/gsm-interface-8051-microcontroller-circuit-code