Step 1: Create an Apple Developer Account (for Non-Profits)
Please go to the following link and follow the steps to apply for an "Apple Developers Account".
For Non-Profit Organizations, the cost is $0 ($99 regular).
Make sure to enable 2 Factor Authentication.
Step 2: Add a new Admin User
1- Once your Apple Developers Account has been created, Login to the following website:
2- Go to Users and Access
3- Click the + sign to add a new user
4- Enter the following Email Address as the new user: firstname.lastname@example.org
5- Select "Admin" as the role
6- Select the checkbox next to "Access to Certificates, Identifiers & Profiles"
7- Click "Invite"