Is there any form/checklist that needs to be sent to customer to fill in and confirm that they are education customer?

There is no form/checklist that needs to be sent to customer for verification. The Customer needs to self verify with the partner that they meet the eligibility requirements of an academic customer

As always, Microsoft reserves the right to claim back the extra discount given to an education customer if the customer does not meet the requirements for academic customer and is hence ineligible for the academic pricing.