Insert order id into a form

Hi,

I have been searching the whole internet for days for this info and I only got more confused. Perhaps you can help me.

Here is what I want to do:

A costumer log in to the My Account page. There I have a link to a form-page. Once on the form-page, the customer can add a note or upload an image. To differ between the customers different orders, I need to populate a dropdown for the customer to choose which order this note or image belongs to.

What is the code I need to get the logged-in-user order id’s and how do I populate a dropdown with the data?