Check the datasheets for voltage levels. ESP32 uses 3.3V so if your devices uses the same you should be good to go.

my gsm module uses something around 3.9 to 4 V, what should i do.

I am using quectal m95 gsm module with esp32 board to create a point to point cellular connection, Can i connect thier TX and RX pins directly or i need to do some volatge level conversions???