This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)

Typing Overscripts

Typing

Type the expression that will have an overscript.
Type .
Click for copyable input
Create an overscript by pressing the Control key and the 7 key at the same time.
Press Ctrl+7 or Ctrl+&.
Click for copyable input
Type an underscore into the placeholder (which is already selected).
Type .
Click for copyable input
Move the insertion point out of the overscript position down to the baseline by pressing the Control key and the Space bar at the same time.
Press Ctrl+Space.
Click for copyable input

Typing

Press the Control key and the 7 key at the same time.
This creates a pair of placeholders, one on the baseline and another in the overscript position.
Press Ctrl+7 or Ctrl+&.
Click for copyable input
Type an underscore into the placeholder in the overscript (which is already selected).
Type .
Click for copyable input
Press the Tab key to select the placeholder that is on the baseline.
Press Tab.
Click for copyable input
Type the expression under the overscript.
Type .
Click for copyable input
Press the Control key and the Space bar to get out of the overscripted expression.
Press Ctrl+Space.
Click for copyable input