Adding Spend Authorization Flexfields

Summary:

How to add additional Spend Authorization Descriptive Flexfields?

Content (please ensuse you mask any confidential information):

Hello, we recently enabled the Authorization option within the Expense module. The project team needs to add several more must-have fields in the "Request Authorization" section as seen in the screenshot below.

How do I go about getting started on this? I tried sandbox but the Flexfields option is grayed out?

Also related to this: usually for Expense Report, an end-user can delegate their Expense Report Submissions, so the Business Manager can submit the expense report on their behalf, are there similar functionality to Authorization?