You should see the option if you click Insert tab | Page Numbers | Bottom of Page (or Top of Page); you may have to scroll quite a bit in the gallery.

If the option isn't there, you can add the required fields manually. First activate the header and footer area, for example by double-clicking the header. Type "Page"; then press Alt+Shift+P which adds the current page number. Type "of" and press Ctrl+F9 to insert field delimiters, { }. Type NUMPAGES between the field delimiters. Select all and press F9 to update fields.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional