A tab
leader is a repeated pattern of characters, such as a series
of dots or dashes, between a tab and the following text.
In the Tabs panel, select a tab stop on the ruler.
Type a pattern of as many as eight characters in the
Leader box, and then press Enter or Return. The characters you entered
repeat across the width of the tab.
To change the font or other formatting of the tab leader,
select the tab character in the text frame, and use the Character
panel or Type menu to apply formatting.