By default, any group participants can send messages and change the group information including, the group subject, icon, or description. However, a group admin can change group settings to allow only admins to edit group info or send messages.
Change the settings for editing group info
Open the WhatsApp group chat, then click the group subject.
Alternatively, click Menu ( or ) in the top corner > Group info.
Click Group Settings > Edit group info.
Choose to allow All participants or Only admins to edit the group info.
Click CONFIRM.
Change the settings for sending messages
Open the WhatsApp group chat, then click the group subject.
Alternatively, click Menu ( or ) in the top corner > Group info.
Click Group Settings > Send messages.
Choose to allow All participants or Only Admins to send messages.
Click CONFIRM.
Note: Participants can directly contact an admin by clicking admins in the group, then clicking the name of the admin they'd like to message.