Hi Wesley,

Yes, you can access your custom field in a mail template. First, create the custom field in the sale order model. Then, select the corresponding mail template that you want to modify. In the content section of the mail template view, you can edit the template code.

To add your custom field, you can use the following syntax:

<span t-out="format_amount(object.custom_field_name, object.currency_id) or ''">Custom Field Value</span>

Replace 'custom_field_name' with the name of your custom field. You can also apply any necessary formatting to the custom field value within the template.

Make sure to test your changes to ensure that the mail template renders as expected with the inclusion of your custom field.

Hope it helps

Yes, all fields are available.

If it's a Sales Order document you should be able to access your new field as 

object.x_studio_werfadres