In this post we will discuss about how to activate document sets
in site collection in SharePoint 2013. Also you can check out:
First open the top level site collecton.
Then select Site Settings from the Settings menu. The Site Settings page appears.
Then from the Site Collection Administration group click on Site Collection Features link. This will open the site collection features
page where it will show all the features available in the site collection.
Select the Activate button associated with the Document Sets feature. The page refreshes and the feature now appears as Active.