There are a number of options that you can set within a Google Group, including advanced options which you can display if required.

Group settings

Advanced Settings

If you enable advanced settings in the group, you will be able to set additional options such as:

To show advanced settings for the group, turn the Advanced option on, in the top-right corner of the screen. 

After making all changes to the group settings, click on Save Changes along the bottom of the screen.