By default, in Word, when you select text and then type anything, the selected text is replaced with what you type. This can be frustrating if you’ve highlighted some text and then accidentally pressed a key and lost your work.
There is a setting for this behavior in Word that is on by default. To turn off this setting and avoid replacing selected text with what you type, click the “File” tab.
Click “Options” on the left side of the “Info” screen.
On the “Word Options” dialog box, click “Advanced” in the left pane.
In the “Editing options” section, at the top of the right pane, select the “Typing replaces selected text” check box so there is no check mark in the box.
Click “OK” to accept your change and close the “Word Options” dialog box.
Now, when you type while some text is selected, the newly typed text is inserted before the selected text.