1. I understand the above macro
2. How to run this macro? should i open any word document
3. I tried but not sure how to run the above macro. Help me with screenshot if possible

See Installing Macros

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Graham Mayor - MS MVP (Word) (2002-2019)
Visit my web site for more programming tips and ready made processes www.gmayor.com

I'm no expert, but I expect the following will work:

Open the Word template you are using—Normal is the default.
Open the VBA editor—Alt+F11.
Paste Graham's code into a module—Module1 is the default.
Save the code in the editor.
If asked to save changes to template, select whatever corresponds to 'Yes'.
Close the template.

If you like, customize your Ribbon by adding the macro to a new button on it.

Open a doc in the folder, then run the macro.