After the release of iOS 6.1.2 update for iPhone, iPod Touch and iPad, Evad3rs has also released updated Evasi0n 1.4 that includes support for jailbreaking iOS 6.1.2.
You can download Evasi0n 1.4 for Windows, Mac or Linux through integrated link.
See also:
How to Jailbreak iPad Mini, iPad 4, iPad 3 over iOS 6.1.2 with Evasi0n
How to Jailbreak iPhone 5, 4S, 4, 3GS over iOS 6.1.2 with Evasi0n
How to Jailbreak iPod Touch 5G, 4G over iOS 6.1.2 with Evasi0n