how can i use a web site with adobe flash on ipad pro?

There has never been ANY Adobe Flash Player support on ANY iOS device.

And Adobe abandoned trying to support Flash Player on iOS loooong, ago.

You would need to find a third party web browser that works through an offsite service that will allow you to view Adobe Flash Player content through a mobile iOS web browser.

Look at Photon Web browser or Puffin Web Browser in the iOS App Store

Be advise that no one here knows how safe or secure these types of Adobe Flash Player supported browsers are, but will get you want you need.

Good Luck to You!

I have an iPad too, im not sure you can..

Not with the builtin browser Safari; it does not support Flash. Perhaps some third-party browser containing support for Flash would work for you; search the App Store.

i have an ipad pro and it wont let me so im guessing, no.