Do you want to download a file using Download() function within your app?
Currently, there is an known issue with the Download function within PowerApps. The Download function would open a file in web browser rather than download the file based on the web address into your local machine.
The user @cjs321 has faced same issue with you, please check my response within the following thread:
I have also posted this issue to my Product Team, the response from @Wyatt Goodin:
This is deliberately prevented by browsers, due a strong security recommendation by the WHATWG specification https://html.spec.whatwg.org/multipage/links.html#downloading-resources If the user has control over the server that serves that file (or knows the person who does), they can add "content-disposition: attachment" to the list of headers on the response, which tells the client that the server expects the file to be downloaded in this way. Returning to CSS for communication with customer.
If the issue is solved in PowerApps, I would reply here.
Community Support Team _ Kris Dai If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.