Read in detail how to manage your Google Group.
The steps are listed below.
Sign in to Google Groups https://groups.google.com/
Click My Groups.
Find the group in the list.
To the right of the group name, click the "Add members" icon to add members.
In the "Group members" section, enter the email addresses of the people to add. Separate multiple addresses with commas.
As you type each email address, Google will look it up in the directory. Click on the correct entry to have the display name included with the email address in the list. This is very helpful when you later view Group members.
Do not enter a welcome message unless you are adding external members. Leave this section unchanged.
In the "Subscription" section, leave the "Each Email" option selected unless you have special requirements.
Leave the "Directly add members" options selected.
Carefully review the list of addresses to be sure there are no typos!
Click Add members.
To the right of the group name, click the "Group settings" (gear) icon.
In the left navigation section, select People > Members.
In the list of group members, check the box next to the members to be removed.
On the top group of buttons, click the "Remove member" (circle with horizontal bar) icon.
When prompted "Are you sure you want to remove this member from the group?" click Remove