How to customize Odoo and edit/remove menus,forms and labels

Hello everyone, i am looking for a way in which i can customize Odoo especially the menus, forms and labels. I tried activating the developer mode, customized the menus but once i restart the Odoo service all the changes(of which i had saved) are lost. Is there anyone who has an idea on how i can interact with the source code so that i can make the changes permanently.

Kindly help @dmgogorza, @dmukungi, @rakib, @amolsatvix, @degbenedio

To edit menu names (caption of the menu)

  1. Get the menu item id that needs to be modified from Settings->User Interface->Menu Items->Search for the menu ->using developer tool icon (bug)->View Metadata->XML ID

  2. In the template of your module add

     <record model="" id="sales_team.menu_partner_form">
         <field name="name">Patients</field>
  3. Restart ODOO. Login to see the changed menu.

Here is the changed menu name (caption) for Sales->Customers to Sales->Patients


Thank you…how can i access this template please?

You can create your own module as mentioned here and have a template in that module.