Why is there no Analytics section visible on my dashboard?

This may occur when you have enabled Multi-Currency on your platform.
When multi-currency is enabled, a few features including analytics do not work. You need to disable the toggle of Show currency To Stores in Preferences in Configure.

How do I enable the notification sound of apps on my phone?

In the case of an android device, click on the app(for a few settings) >> app info >> notification settings >> allow sound.

In the case of IOS go to phone settings >> click on the app >> and you will get an option of alert which you can configure accordingly.

Can I share order invoices with my customers over chat in case they requested the same?

You can share the Order invoices or any other documentation over Hippo chat. Make sure you have enabled it under integration. 

In your Hippo chat dashboard Click on + Icon and below the Chat bar and select the Invoice or any other file that you want to share and click on send the file.