What are the steps to add Shared Line Appearance (SLA) or a shared mailbox for an extension, and where in the domain interface can this configuration be accessed?

To add Shared Line Appearance (SLA) or a shared mailbox, log into the domain, navigate to Inventory, and access Phone Hardware.

Choose the desired extension in Snapbuilder and edit one of the buttons, selecting 'Shared Line Appearance.' Assign the extension and label accordingly.