After all this time I've finally upgraded my computer to Windows 10, but I'm having trouble finding how to edit an Html Document. When I right click the file there is no 'Edit' option, so how can I edit it?

That's easy.

Uninstall Windows 10.
Reinstall Windows 7.
Use your favorite editor

Assuming this is a serious question, I don't know which kind of Html editing you were used to in Win 7...
Html files itself are just plain text files, which you edit with the Notepad editor that comes with Windows, some people use WYSIWYG editors for that (where you can do the editing putting objects together the "visual way" or comfortable text editors with syntax highlighting etc.

Google "comfortable html editor" brings up sites like that:

http://sitebeginner.com/build/freehtmleditor/

Which ever HTML/Text editor you end up chosing I strongly suggest NOT using Microsoft Word as it produces some of the most Microsoft only dependent HTML code ever seen, which generally does not play well with non-Microsoft brand web-browsers.

Typically in Win10 you right click and use "Open With" and select the program you want to use. Alternately, you can put shortcuts to the editors you want in your "Send To" folder (same as on Win7) and send files to them. Personally, I edit Html in visual studio (if you have a hammer...) so I drag the files I'm working on into it.

Tlaero