^^ To: All 19 million scientists and researchers at RG platform!

It depends on what type of software you are developing. If you're making a web application, I recommend QRCode.js.

Source code and instructions are available here: https://github.com/davidshimjs/qrcodejs

You can check Qr code generator at goqr.me.

http://goqr.me/

Dear shivendra,

If you need a library, I strongly suggest you to use the zxing library. It is written in java, and allows you to generate QR codes with any level of error correcting code, version, output PNG dimension, etc 

I like all above generators, but also I like this one:

QR Code Generator

https://www.the-qrcode-generator.com/