To include numbering prefixes from higher levels, enter text or click at the start of the Number box and choose Insert Number Placeholder and then select a Level option (for example, Level 1), or enter ^ and then the list level (for example, enter ^1). In a list with first levels numbered 1, 2, 3, and so on, and second levels numbered a, b, c, and so on, including the first-level prefix in the second level renders second-level numbers as 1a, 1b, 1c; 2a, 2b, 2c; 3a, 3b, 3c.
One of the easiest ways to begin applying numbers is by starting to type a numbered list. Word recognizes that you are creating a list and responds accordingly by converting text that you type into numbered items. The number scheme, delimiter characters that mark the beginning or end of a unit of data and formatting are all based on what you have typed.
Numbering and Section options are available in the Pages Panel menu. These options allow you to define what page starts a section and how it should be numbered. A Current Page Number marker must be set on pages in order to use this feature. The Current Page Number is a special character inserted in a text frame on a page or master page (recommended) where the page number will appear, by selecting Type>Insert Special Character>Markers>Current Page Number.
Many Office programs will detect when you start a numbered or bulleted list and helpfully automate it, so that when you press Enter, new list items are automatically indented and bulleted or numbered. If this behavior isn’t actually all that helpful for you, and you’d rather control your own list-making without Office’s help, you can turn to your autocorrect options.
The above steps are the most basic way to add a very basic page number, but if you follow a few tricks then you could save yourself even more time and get the job done even faster. For one thing, the page number you’ve added is only for one page, and if you used that method you’d spend ages adding page numbers to the whole document. To add page numbers to all pages quickly and format them all equally, follow these steps:
You will occasionally want to place an unnumbered paragraph in the middle of a sequence, but the moment you hit Enter, another paragraph number pops up. To fix this, toggle paragraph numbering off by pressing the paragraph numbering button you used for the previous paragraph. (If you use the button’s drop-down, choose None as the numbering scheme.) Unfortunately, the paragraph settings won’t revert to Normal here; it’ll usually have the paragraph indented 0.25. Use the keyboard shortcut CTRL+Q to strip paragraph settings out, then revise the formatting as you wish.
To save the list style to a template so you can use it with other documents, select the list in the document. Access the Multilevel List dropdown and choose Define New List Style. Enter a descriptive new and select the New documents based on this template (at the bottom). Once you click OK, the multilevel list style will be available in all new documents.
See Word's Numbering Explained by John McGhie, MVP - comprehensive and not pretty (Downloadable pdf file in letter size) - Reading this is vital to anyone attempting to use automatic numbering or bullets in a law office setting or other places where the documents are likely to be reused or heavily edited. See also How to Create a Template with a downloadable template with style-based numbering.