If you are referring to static text, it's the same as in previous versions:
just type it into the "Number format" box (of the appropriate dialog box).
If you have created single-level numbering without attaching it to a
paragraph style, place the insertion point in the numbered list. On the Home
tab, click the arrow to the right of the Numbering button, and then click
Define New Number Format.
If you have created single-level numbering and attached it to a paragraph
style, click Format, Numbering in the Modify Style dialog box, and then
click Define New Number Format.
If you are referring to multilevel (outline) numbering, place the insertion
point in the first level 1 paragraph of your list (for heading numbering,
this means the first Heading 1 paragraph of the document). On the Home tab,
click Multilevel List | Define New Multilevel List. Select the level that
you want to modify.
