I agree completely with Charles: modifying the Normal style to be numbered is not a good idea. For one thing, Normal is the parent (based-on) style for many other styles, and you probably don't want numbering to be included with most of your styles.

Instead, set up numbering so that each level is associated with a paragraph style. You don't have to use the built-in headings. Actually, if you are setting up a multilevel list format which is not intended to be used as a set of headings, don't use the built-in headings. The principles discussed in Shauna Kelly's article apply to any set of nine styles.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional