Can I make an Excel VBA macro available to all workbooks?
No addon making required!
Store it in a special workbook called Personal.xlsb
Steps:
You can make macros available across all your workbooks, by saving them to a special workbook that Excel loads each time it is opened.
YouTube : How to Create a Personal Macro Workbook in Excel and Why You Need It
Office Support : Create and save all your macros in a single workbook
Office Support : Copy your macros to a Personal Macro Workbook
There are a few ways to do this, here's one link that explains how to create an Excel Addin with VBA code. You can also create other types of addins in other ways, but this is the simplest. There are thousands of references you can search for that talk about how to do this.
When you record a Macro you can store it afterwards in your Personal Macro Workbook. When you Exit Excel it asks if you want to store it, once you click yes the Macro will become available for all workbooks under Developer => Macros. See also Microsoft support