How to automatically approve a Standard Purchase Order from requisition

We want to automatically approve Standard Purchase Orders from requisitions.

Tools that calculate what we need to buy automatically create a requisition, but we have to enter and create an order from them and approve it by the appropriate person in the hierarchy.

We want this tool/mechanism to have the right to automatically create an order from requisition and approve this order, without the intervention of people in the hierarchy - only when created for the first time - after any change, for example by the buyer, it would require reapproval.

We would like to create a separate style in which to do this.