You can add new participants into a group in various ways:
2. Typing "+" in the message field.
Click on the Kebab menu (three dots) in your group chat.
You can now search and select the participants that you want to add to the group and click Add.
Type "+" in the message field in the group
You can now click on the participant that you want to add into the group.
You will see the a + sign along with the name of the participant that you want to add.
Once you press send, you will see a pop-up message. Click "Yes, add to this chat" to add the participant in the group.
Click on the number of participants under the group name.
Click on Add Participants.
Click Add to add the new participant to the group.