A "designation form" is a document that you fill out to officially assign or allocate someone or something to a specific role, purpose, or position. Full definition
Once you've determined who you would want as your beneficiaries, you should specify them on the life insurance beneficiary designation form. (valuepenguin.com)
You want a copy of the original beneficiary designation form. (marketwatch.com)
However, you and your representative must complete an Applicant Representative Designation form. (studentaid.ed.gov)