Tab settings is a paragraph level formatting attribute. To set the default,
you would need to focus on a particular paragraph style (such as Normal),
and change its default tab settings, and instruct Word to copy those changes
to the underlying template.
For example... the default template in Word 2003--unless you specify
otherwise--is Normal.dot. The default style--unless you specify
otherwise--is named Normal (which has nothing to do with the fact that the
template is named Normal.dot -- just an unfortunate and often confusing
choice of names).
So... to set the default tabs that you would get when using the Normal style
contained in Normal.dot, you could do the following:
1. In a document based on Normal.dot, choose Format - Styles and Formatting,
right-click on Normal, and choose Modify.
2. In the Modify Style dialog box, click to enable "Add to template".
3. At the bottom of the dialog, click Format - Tab2. Set the tabs as
desired.
4. Click OK - OK.
Later, when/if prompted to save changes to Normal.dot, say Yes.
Some may advise you not to change the Normal style. They might be right,
but, if you weren't supposed to change it, it wouldn't be changeable. But,
keep reading... changing Normal can have unintended consequences.
Others would ask WHY you want to change the default tabs. If you're doing it
to accomplish paragraph indentation, then I would suggest that you not use
tabs for that. Instead, change the Indentation settings for the paragraph.
Back in step 3, choose Format - Paragraph, instead. In the Indents and
Spacing tab, set Special: to First line, and set By: to the desired indent.
But, keep in mind that many many styles are based on Normal, and by changing
Normal, some settings will trickle down, affecting documents in
unanticipated and unintended ways.
By using Normal for most formatting, rather than carefully choosing styles,
you open documents up to sudden and unexpected changes. For the most part,
it's advisable to choose styles carefully and to differentiate how styles
are used. This gives you leverage, and almost as important, it can prevent
that same leverage from unexpectedly messing up the formatting of a
document.
Good luck!