How to version control with WordPress

Hi,

I want to set up a system where a developer can work on a separate server on a wordpress website.

My question is: If in the meantime changes are made to the live site (like plugin updates, new plugins, new posts, new comments, etc), how is one able to import a new feature (e.g. a new page) from the development server on the live site while making sure that previous changes on the live site don’t get deleted?

I am looking to understand how this all works. In a sense, I would like to have some kind of version control system.

Thanks in advance ??