By default, admins will not be allowed to approve their own reimbursements. We recommend this setting as a necessary control for your company. If you would like to allow admins to approve their own expenses, go to Spend Controls > Reimbursements, and toggle on.
Reimbursements by default will require an approval for employees and managers unless you make changes within your approval flows for reimbursements to require more than one approver, at which point all reimbursements will follow your rules.