I have a huge document in which I want to ensure that if any text has following attributes, then it should be set as Heading 1.
Font Size: 12
How can this be done in MS Word?
What exactly do you mean by "Heading 1"? Should the text be converted to a header? You can search text that matches your criteria by using Word's search and replace feature. Then replace them accordingly. Follow this guide.
1.Start recording a macro. See this for help.Do set a shortcut key to start the same.