Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19b/oapfm/project-foundation-configuration-define-project-resource-breakdown-structures.html#OAPFM180158_2 Why can,t I find persons in the list of resources when I enter team members, planning resources, or person rate schedules?
You can,t find persons in the list of resources when you enter team members, planning resources, or person rate schedules in the following situations:
The administrator didn,t assign a department while creating users. Persons must have an active assignment and be assigned to a department in Oracle Fusion Human Capital Management before they can be added as team members or entered as resources on the planning resource breakdown structure or person rate schedule.
The resource isn,t active in Oracle Fusion Human Capital Management because the current date is before the effective date of the resource. If you want to include persons who will start in the future, select the Include people with future-dated effective start dates option when you search for the person.
Persons assigned as project managers aren,t active as of the project start date.
The assignment of the person is terminated, and an appropriate value isn,t set for the number of days to display people with terminated assignments. You can set the profile value appropriately at the site profile level using the Specify Number of Days to Display People with Terminated Assignments task in the Setup and Maintenance work area.

Ref: https://docs.oracle.com/en/cloud/saas/project-portfolio-management/19b/oapjb/create-customer-contract.html#OAPJB70183 Bill Plan - Create a bill plan within a contract that uses the invoice method you require. Assign the bill plan to one or more contract lines. A set of instructions on a contract that define how to invoice a customer. Multiple contract lines on a contract can use the same or different bill plans. Invoice Method is used in creating Bill Plan - not a separate setup.
Billing Controls - Contract feature that controls the types of transactions, dates, and amounts a customer may be invoiced for and revenue can be recognized for a contract or contract line. Define billing controls at the contract or contract line level.
Topic - Creating a Contract for Percent Spent Invoice and Revenue Methods: Worked Example This example describes a scenario where transactions for a contract line need to be invoiced and the revenue recognized using the percent spent method.
What are the revenue and invoice method classifications? Percent Spent What is the billing extension calculation level for the contract line and project association? Project level Summary of the Tasks Create a contract, create the percent spent contract lines, create the bill plan, create the revenue plan.
Prerequisites
Create a project.
Create the project plan for percent spent revenue. Specify the plan type on the percent spent billing extension.
Create an approved cost budget.
Create cost and burden rates.
Enter labor and expense transactions for the project.
Collect costs for the transactions.
Configuration Steps
Creating the Contract
Creating the Percent Spent Contract Lines
Creating the Bill Plan - A set of instructions on a contract that define how to invoice a customer. Multiple contract lines on a contract can use the same or different bill plans.
Creating the Revenue Plan - Common set of instructions for recognizing revenue within a contract. Multiple contract lines on a contract can use the same or different revenue plans.
Invoice method classifications determine how transactions are invoiced. The invoice method determines how invoice amounts are derived.
Enter an invoice method on a bill plan, which you create for a contract and assign to contract lines to provide a set of instructions for creating an invoice.
Create billing controls for a contract or contract line to define the valid transaction dates, billing resources, and amount limits for transactions associated with the contract.
Generate invoices to calculate the invoice amounts for a contract.
The following figure illustrates the components of a project and a contract that determine invoice amounts, and the relationships between the components.