How can I sort items in the kanban view? For example sort task in the Kanban view in alphabetical order?
You can change the default sorting order of the kanban cards by modifying the kanban view definition. Just add a "default_order" attribute to the kanban node, with the comma separated names of sorting fields.
<field name="arch" type="xml">
see https://www.odoo.com/documentation/8.0/reference/views.html#kanban for the reference