Please be careful on other online websites while buying cheap Arduino Clones/Counterfeits. Though Clones/Counterfeits are cheaper, they fuzz out and die away soon while also being unstable. It's always recommended to shell in some extra bucks and get the Original Arduino Boards.
The Arduino UNO is the best board to get started with electronics and coding. If this is your first experience with electronics and coding, the UNO is the most robust board you can start playing with. The UNO is the most used and documented board of the whole Arduino ecosystem.
The Uno is a microcontroller board based on the ATmega328P. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.. You can tinker with your UNO without worrying too much about doing something wrong, worst case scenario you can replace the chip for a few rupees and start over again.
The Uno can be programmed with the Arduino Software (IDE). Select "Arduino/Genuino Uno" from the Tools > Board menu (according to the microcontroller on your board). For details, see the reference and