This tutorial talks about the Auto Replace feature available in Google Docs. Using this feature, Google Docs users can add abbreviation and their corresponding words. For example, if you want to the entry da to be replaced with digianswers then you can do the following
Click the Tools menu and select Preferences from the displayed menu list.
In the Preferences Window, make sure to mark the check box with label as Automatic substitution.
And type “da” in Replace text box and the corresponding entry “digitalanswers” in With text box. Click OK button which is available at the bottom of the Preferences window to save the changes. Now when you type “da” in the document, it would be replaced with “digitalanswers”