You can add channels or supergroups to directly communicate with your users. Learn how to do it here. Channel link can look like:
You can now use bot url or username as well.
You can add different stickers for your messenger.
Find stickers here
You can specify links of this format:
IMPORTANT! Uncheck checkbox below to use your own custom 'Welcome' screen.
Specify the link that will appear when you invite a user to your application.
List of themes: