To add action and menu in Odoo
Action- There are different types of actions in Odoo:
1- Window: Opening of a new window
2- Report: The printing of a report
3- Custom Report: The personalized reports or RML Report: The XSL:RML reports
4- Execute: execution of a method on the server side
5- Group: Gather some actions in one group
In your .xml file use these code to show the action in your form in Odoo

<!-- Your Action Window Definition -->
<record id="action_123" model="ir.actions.act_window">
    <field name="name">Your Module Name</field>
    <field name="res_model">your.object</field>
    <field name="view_type">form</field>
    <field name="view_mode">list,form</field>
</record>

Menus- In your .xml file use these code shows the menus in your form in Odoo

 <!-- Action Menu Item Related To Above Action Window -->

<menuitem action="action_123" id="action_menu_123" parent="write_the_parent_menu_id"
name="Readable Text" 
sequence="1"/>