Tableau uses default formatting that includes default fonts, colors, shading, and alignment. Additionally, there are several levels of formatting you can customize:
Workbook level: The following type of formatting comes under this category:
Default field formatting: Using the drop-down menu on any field in the Data window, go to Default Properties | Date Format or Default Properties | Number Format. This sets the default format in Tableau's metadata and will be applied to any view where custom formatting has not been applied.
Story level: When viewing a story, go to Format | Story (or Story | Format) to edit formatting for story-specific elements.
Dashboard level: Dashboard-specific elements can be formatted. When viewing a dashboard, go to Format | Dashboard (or Dashboard | Format) to specify the formatting for dashboard titles, subtitles, shading, and text objects.
Worksheet level: We'll consider the various options. The following types of formatting are...