Ok Here we go.
In an app I place a label and give it the text Value of
"SGVsbG8gV29ybGQ="
Then hop over to PowerAutomate, click Create > Instant Cloud Flow, and select PowerApps
When this opens, delete the top step, PowerApps, it will give you a warning, throw caution to the wind and continue anyways.
Now click the + at top, and search for powerapps, and select PowerApps (V2) Give this a text option in it, and give it a name you liek.
click + again and search for initialize variable. Set its name to whatever you want, mines 64String, Type is string, and Value click in the box and then on the right clicjk expression, start typing base, and select base64 to string, once clicked type a ( and it will automatically Put () click inside those and then just above to left select dynamic content and choose the base64 output from the powerapps step 1shoudl look similar to this when done
base64ToString(triggerBody()['text'])
Next click + again and choose respond to a powerapp or flow
add a text, and give it the value of output of our previous step.
whole thing when done looks like this
Save this flow, then exit it and make sure its turned on, turn it on if not
Now go back to powerapps.
add a flow,
now add a button, and make it's OnSelect
///Label17.Text is where I pasted my base64 Code to test
///.yourstring yourstring is name of the returned variable we setup in our flow
UpdateContext({new64string:'64toString'.Run(Label17.Text).yourstring})
now anywhere in the app you can reference new64string and it will show you the decoded base64, in my example you will get,
Hello, World
