Hey @jeesim2,
Welcome to the community 
A workflow can trigger another workflow if you use the “Execute Workflow” node at the end of it, A node however would only exist in the workflow so you can use the same node in multiple workflows but it wouldn’t share the data between them (assuming this is what you mean).
There is no guidelines for using VCS with n8n but we are currently looking at options to allow this, At the moment you can use the API, CLI or UI to export and import workflows that you could store in git or anywhere else but how you would actually use it would be up to you and what fits your requirements.
If you are interested in different environments and VCS it might be worth checking the survey here: Help us design our upcoming environments feature — take this 5min survey