When you run a simple python script that uses a=input('text: ') inside kdevelop for windows (not tested in Linux), no 'text: ' output is shown in the run panel, and there is no way to fill the input using the keyboard.
KDevelop's output view does not support input, that's the case on all operating systems. Regarding displaying the message, you probably have to call sys.stdout.flush() to get it to display.
Thank you for reporting this bug in KDE software. As it has been a while since this issue was reported, can we please ask you to see if you can reproduce the issue with a recent software version? If you can reproduce the issue, please change the status to "REPORTED" when replying. Thank you!
The output view is only output.