Hi Sharma! welcome aboard.
https://blog.kolide.com/osquery-under-the-hood-c1a8df46bb7a might be a good intro to how some of it works under the hood. That’s got some other links to additional writing. (To be upfront about it, that’s a blog post from my employer)
osquery is a fairly mature project, which can make it hard to tell how to start contributing. I’d recommend any of the following:
• peruse https://github.com/osquery/osquery/labels/good-first-issue
• Play with osquery!
• Are there docs you want to improve?
• Are there features or bugs you encounter?