ESP8266 ESP-07 does not respond to commands
The esp8266 is without AT firmware. Even with SoftwareSerial at 115200 baud you should see "ready" from AT firmware and get some response to AT commands.

This esp8266 module adapter is simple to flash. It makes the 5 V to 3.3 V conversion for power and RX pin and has a program switch (io 0) and a reset button to put the esp8266 into flashing mode. 

Use an USB-to-TTL-Serial adapter or an Arduino with USB chip to connect the adapter to PC. Then switch to "program" and reset it and it will be in flashing mode.

You can download the AT firmware here. I recommend ESP8266 NonOS AT Bin V1.7.1. Don't try 2.0, it is very different (ESP32 AT firmware build for esp8266).

To flash it, use esptool

The command to flash the AT firmware binaries to any module with at least 1 MB flash memory is:

esptool.py write_flash --flash_size 2MB-c1 0x0 boot_v1.7.bin 0x01000 at/1024+1024/user1.2048.new.5.bin 0x1fb000 blank.bin 0x1fc000 esp_init_data_default_v08.bin 0xfe000 blank.bin 0x1fe000 blank.bin


don't wonder about the 2MB-c1 setting and don't change it. The AT binaries are build for 2MB-c1 partitioning. On 1 MB flash it will not support AT firmware OTA update.

If you want to use the Espressif Flash Download Tool, use the same settings as on esptool command line.