As you know, creating a formatted AutoCorrect entry means that you add "example" content in a file. How Word treats formatting depends on how you formatted the example entry in the file. For example, if you applied a unique style and then created your AutoCorrect, inserting the AutoCorrect in another file will produce the same formatting in the new context, as long as the style doesn't exist in the "target" document. If the style does exist, the settings of that style in the target document determines the formatting.

Similarly, if you didn't apply a specific style but simply made use of the document defaults when you created the entry, chances are the formatting may change when the AutoCorrect is inserted in another document.

If the AutoCorrect was created with direct formatting, applied (say) via the Font and Size controls on the Home tab, that formatting is likely to be preserved when the AutoCorrect entry is added in another document.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional