Deploying my SharePoint application from my development, UAT and production environment

I am somhow new to SharePoint and I have read on an online training which mentioned that “Creating a new content type using feature will improve re usability, since it will enable us to transfer content types from one environment to other”. So this raise the following question which I need to know in the future:-

1. If I create a new content type directly from the SharePoint administrator (not using Visual studio),  then will I be able to transfer the newly content types from my development to my UAT environment?

2. Let say that I currently have three versions of my sharePoint application on the three environments. If I created new items, lists and content types in addition I have created a new wiki site in my development environment. And I have unit tested these on my development environment. Then how I can only transfer the newly added components to my UAT environment which include:-

    • A wiki site

    • Content types

    • Document library
    
    A• And updating privileges on an existing team site.

Best Regards