The module has a 3.3V voltage regulator circuit and 5v-3.3v onboard level conversion circuit.
Yes, the module can be used with Arduino UNO R3 or compatible board without needing an additional level converter, as it is integrated in the module.
The module has Vcc, GND, TX and RX, so it means it uses a serial protocol for Arduino communication (and you will need two pins in the Arduino). Other pins in the ESP-01 are not needed in this scenario, but you still have access to them via the 8-pins female connector on the module.
It's totally plug and play.
Addendum: The old way
This how you connect a standard ESP-01 with an Arduino. The module you are looking at include all the resistors and also connect the CH_PD pin to Vcc. You only need to connect four pins. It saves you time, money and space.