How do I manage group chat settings in Skype on mobile or tablet?

Android (6.0+), Android tablet, iPhone, and iPad

•  Add or update a group picture - Tap the group picture to upload a photo or remove the photo altogether.  
•  Change your group name - Tap the Edit button next to your group name to type a new one. 
•  (Android)  (iOS) Share link to join group - Tap Share link to join group, and in the Share and connect window, enable Share group via link, then you can choose how you want to share it:
  • Copy to clipboard
  • QR Code
  • More - Send as SMS, email, or through another app.
•  Start call - Tap Start call to start an audio or video call with this group.
•  Send a message - Tap Send message to send a message to this group. 
•  Schedule a call - Tap Schedule a call to send this group an invite for a call on a specific date and time.
•  Search in conversation - Find a specific message in your chat.
• Add participants - Tap Add participants to include up to six hundred additional participants in your group conversation.
• Group Gallery - Tap Show more in the Group Gallery to view all the images, links, and files that have been shared to this group chat. 

You can also hide your group chat to remove it from your recent chat list.

Android 4.0.4 - 5.1

•  Add or update a group picture: Tap the group picture to upload a photo or remove the photo altogether.  
•  Change your group name: Tap Edit next to your group name to type a new one. 
• Notifications: Turn notifications on or off to receive an alert anytime you receive a new chat in this group. 
• Share group via link: Tap Share group via link to share an invitation link to your group chat.
• Chat history: Allow everyone to see the chat history. 
• Delete group: Delete the group chat.
• Leave group: Leave the group chat. 
• Add People: Tap Add people to include additional participants in your group conversation.

Android (6.0+), Android tablet, iPhone, and iPad

• Hide conversation: You can hide your group chat to remove it from your chat list.
• Notifications: Turn notifications on or off to receive an alert anytime you receive a new chat in this group. 
• Smart Notifications: With Smart Notifications on, you will only be notified anytime someone quotes you or @mentions you in this group. 
• Add to favorites: Add this group conversation to the top of your Chats tab. 
• Chat history: Allow everyone to see the chat history. 
• Share group via link: Turn this option off to prevent group members from creating and sharing an invitation link for this group. 
• Allow joining for guest users: Turn this option off to prevent users with guest accounts from joining this group.
• Leave group: Leave the group chat.