To customize Odoo, you must first activate developer mode. Once you enter this mode, Odoo will provide you with a lot more onscreen information as you navigate through the interface. This mode also allows you to make changes to the database and store that information in a file.

To activate developer mode, click on the Settings menu. On the far right you will see a panel that contains information about the Odoo installation. At the bottom of the panel, you will see the link to Activate the developer mode:

Once you have entered this screen, you can click on Activate the developer mode to begin customizing Odoo.

Odoo recognizes that you are in developer mode by adding ?debug=# to the URL in your web browser. Additionally, Odoo changes the information that is provided when you hover over various fields in the interface. For example, when viewing a sales order record while in developer mode, you can move the cursor over the Confirmation Date field to reveal details about how that field is represented internally in Odoo, as shown in the following screenshot:

The preceding screenshot demonstrates how Odoo displays information while you are in developer mode. In this example, we can see that the Confirmation Date field is named confirmation_date and that the field belongs to the sale.order object. Additionally, we can see that the field type is Confirmation Date and that there are modifiers assigned to the field. This type of information will be of great value as you continue to customize Odoo.