OK, so your question is why does Freeform launch when you open DoorDash? I saw a brief search reference (without opening the link) that mentions Freeform helps some apps display content using picture-in-picture mode. I don't use DoorDash, so don't know if that's a feature. If no one else chimes in, you could try uninstalling it (unless you're using Freeform as a standalone app too), or possibly contact DoorDash support to ask about it.