How can I add groups to TextExpander?

TextExpander offers several optional snippet groups (predefined groups) you can add, like Autocorrect and others you can learn more about here.

To add a predefined snippet group:

Open the TextExpander window and click on the plus + button in the lower left corner.
Select Add Predefined Group…
Click on the group you want to add.

Or, you can go to File > Add Predefined Group… and click on the group you would like to add.