If you mean importing a thesis, if you can find a place where it’s hosted online, such as a university repository or ProQuest or Thesis Commons, Zotero can import metadata from there.

You go to the thesis on WhiteRose (https://etheses.whiterose.ac.uk/24886/ ) and then click on the Save to Zotero button (an academic cap in this case) as you would for any other reference. https://www.zotero.org/support/adding_items_to_zotero#via_your_web_browser

You could just start off with Google Scholar:
https://scholar.google.com/

Yup, I literally pasted a chunk of your post into Google to find this - first hit.