STM32 BLE profiles - multiple sensors active ST BLE Sensor App
This is a bitmask so set each bit to identify what characteristics/features you want to export from the board:
0x000C0000 sets bit18 (Temperature) and bit19 (Humidity)
So:
 /**
 * Advertising Data
 */
#if (P2P_SERVER1 != 0)
static const char local_name[] = { AD_TYPE_COMPLETE_LOCAL_NAME ,'T','R','Y','P','I'};
uint8_t manuf_data[14] = {
    sizeof(manuf_data)-1, AD_TYPE_MANUFACTURER_SPECIFIC_DATA, 
    0x01/*SKD version */,
    CFG_DEV_ID_P2P_SERVER1 /* STM32WB - P2P Server 1*/,
    0x00 /* GROUP A Feature  */,
    0x0C /* GROUP A Feature */, // Enable Temperature bit18 and Humdity bit19
    0x00 /* GROUP B Feature */,
    0x00 /* GROUP B Feature */,
    0x00, /* BLE MAC start -MSB */
    0x00,
    0x00,
    0x00,
    0x00,
    0x00, /* BLE MAC stop */
};
#endif