You don't need to do anything.
When you create a GitHub issue via Marker.io, we will automatically grab and include all the relevant data about your browser, operating system and the web page you're capturing into your GitHub issue.
Here is a list of the data we include in your GitHub issue:
Page URL
Browser Version
Screen Size
Viewport Size
Zoom Level
Pixel Ration
Operating System + version
User Agent
Here’s an example of a well-documented bug report in GitHub created with Marker.io: