Double lines, which are often used to set off a heading or divide segments in
a bulletin, can easily be created in MacWrite. To do so: hold down the
command key while pressing the letter U to toggle on the underline operation,
or choose Underline from the Style menu. Next, hold down the Shift key while
pressing the hyphen/line key (to the left of the = key); you should see a
double line move across the screen.
Creating the same effect under a word or a group of figures in a column can
only be approximated. First, enter the double line for two or three spaces.
Then enter your figures with the Underline option toggle on to get a single
underline, and then follow with a double line for two or three more spaces.
This suggestion was reprinted from the Open Window column in the December
1984 issue of MacWorld.