When you apply for the PMP, and it is time to document your 4500 hours (if you have a college degree) or 7500 hours (if you do not have a college degree) of leading or directing project tasks, you will be asked to indicate the number of hours in each of the domain areas (Initiating, Planning, Executing, Monitoring & Controlling, Closing).
So, let's say you are using three different projects as proof of your experience of 4500 hours:
- Project A, 1000 total hours
- Project B, 2500 total hours
- Project C, 1000 total hours
You will be asked to provide a short summary description (300 words max, I believe) of your work in each project, and the hours-per-domain for each project. It could look like this:
- Project A, 1000 total hours, 200 each in all 5 domains
- Project B, 2500 total hours, 800 in Executing, 1500 in Monitoring & Controlling, 200 in Closing
- Project C, 1000 total hours, 100 in Initiating, 200 in Planning, 700 in Monitoring & Controlling
In other words, you only need to indicate experience in all 5 domains across all projects, not in each project.
The only way you will be asked to prove this, at the time of your application, is by saying so on the form. No upfront proof is needed; it's expected that you are completing the form truthfully (and ethically).
If you are randomly selected for audit (I was), then you will be asked to have the contact person for that project (which you will have indicated on the application already) review and sign off literally on that exact same delineation of hours and summary description of your work on the project (it will be a printout of that part of the application).