That is purely a matter of which font you apply to the text. Most
fonts are "proportional", in which different letters have different
widths. Only a relative few are "nonproportional" or fixed-width. The
most commonly available nonproportional fonts are Courier New and
Lucida Sans Typewriter.
However, in many nonproportional fonts the digits are all the same
width so that they will line up in columns, as long as you get the
rightmost digits to align. The tool to make that happen is the
decimal tab. At the left end of the horizontal ruler is a button with
what looks like a bold L on it. Click that button several times until
you get an upside-down T with a dot. Then click on the ruler at the
position where the units digit should align. Then press the Tab key
and enter your number; hit Enter, hit Tab, enter the next number;
etc. See
http://word.mvps.org/FAQs/Formatting/SettingTabs.htm for
more info.