Download Here:
https://flex.amazon.com/app/download-app
I see it asked all the time. If your having issues with the app and need to re-download here’s the link from the official Amazon Flex FAQ’s page. Be sure to download only from Amazon. I’ve seen the file hosted on other websites and you just never know what it might contain.
Amazon Flex FAQ Page Here:
https://flex.amazon.com/faqs/
Happy Flexing. Be safe.