First of all, if you don’t have an ESP8266 WiFi module then you can purchase a pair online from https://amzn.to/2Ncwfcm at lowest prices.
You will also need a LF33CV regulator for voltage conversion, get it from https://amzn.to/2NfJWHs
ESP8266 operates at 3.3V and consumes around 150mAmp current, for designing of its power supply we can use LM1117-3.3V Low drop out linear regulator having max current capacity of 800mAmp.
You can also use LF33CV in place of LM117 if required.
When connecting ESP Module to micro controller always remember to shift the logic level at RX pin of ESP module from 5V to 3.3V otherwise the pin will eventually get damaged. Just follow the following diagram and you will have nothing to worry about.
You can make a simple adaptor board with built-in regulator and to convert TTL logic into 3.3V using the above circuit diagram. We used LF33CV as voltage regulator for our purpose. Only 4 pins are required for data communication i.e. VCC, Gnd, RX, TX.
If you want to learn how to connect ESP8266 Module with your computer / laptop then check out this article.
You can also make a 3.3v compatible adaptor eliminating the need for a regulator (Check out this article for details)