Hi,

In Odoo, the fields email_from, email_to, and partner_to are not mandatory in email templates for the Task model.

email_from: Defines the sender's email (defaults to the user's email if empty).

email_to: Specifies the primary recipient, such as the task assignee or customer.

partner_to: Used to send the email to a partner linked to the task, like a customer or vendor.

For more help on creating email templates step-by-step in Odoo 17, you can refer to this blog: https://www.cybrosys.com/blog/how-to-create-an-email-template-in-odoo-17

Hope it helps