Updates & Multiple Forms for a Sheet

Hello, I'm working on a somewhat complex workflow and need some help.

I want to send an order form to a customer and when they return the form, track it on an Orders sheet (pretty basic).

Once I know my order has been picked up from the supplier, I'd like to send the recipient an follow up for updating on when they installed their product, location, and ideally have them submit a picture of their install.

1) How do I tie the update information to my order number (key field)?

2) How would I generate this request and send it to the customer using all the data from their order?

3) How would they attach their photo to the form to upload?