Standardise Processes Using Document Templates in SharePoint Document Libraries

[@HollyMcClane-Gennaro]

Thank you for information!
I have a question if you may.
If I load a document template, then delete it (through ... menu in "Edit New menu") and try to load it again SharePoint suggesting to replace the existing one or save both templates.
It looks like the template file is not deleted, only the menu item from the “Create” list is deleted.
I couldn't find where this templates are stored.
Would you kindly answer how to find it and remove it completely. And probably how to view all documents template that are uploaded for a specific library.