emSigner is a tool GST portal uses to digitally sign for all GST registration and filing purposes.
Java version - Java 1.6 JRE 1.6.0_38+, Java 1.7, Java 1.8
Access - Allow Admin access to emSigner on the computer
Ports - Any of these - 1585, 2095, 2568, 2868 or 4587 have to be free.
Access link - https://www.gst.gov.in/help/docsigner
Click on Click here to download for your respective OS
Click on the downloaded file
On the emSigner setup wizard, click on Next twice and click on Install
emSigner Download Page