Yes, you can potentially use built-in approval workflows and automated actions to send an automated email when a PO enters the approval stage, even within the Odoo Standard edition.

Here's how you can approach this:

• Built-in Approval Workflows: Ensure that you have properly configured the approval workflows for purchase orders in your Odoo Standard edition. This typically involves setting up the necessary stages and conditions for when a PO requires approval.
• Automated Actions: Utilize Odoo's Automated Actions feature. You can create a new automated action that triggers when a purchase order enters the "pending approval" stage.
  • Trigger: Set the trigger for the automated action to be "On change" of the PO's status/stage field.
  • Action: Configure the action to "Send Email." You'll need to create or select an appropriate email template. In the email template, you can include details about the PO (e.g., PO number, creator, amount) and a link to the PO in Odoo.
  • Recipient: Define the recipient of the email. You'll likely want to use a dynamic expression to fetch the manager of the user who created the PO. This might involve accessing related records or using a predefined field that stores the manager's email address.