code editor/ IDE problems

[snippsat]

I tried using IDLE, from the 3.6.4 download package, which lets you run code with the simple press of the enter key, but it
won't let me highlight and change, or delete anything I have typed, once it is in the editor.

That because it starts in interactive mode,you most start file window.

IDLE is an embarrassment for Python,and should have been removed or replaced.
Thonny, Pyscripter, Spyder is simelar to IDLE just better.

As mention bye @Larz60+ there is lot choose from PyCharm(free community edition) is good.
What i use is VS Code which is also very good my quick review.
One Python extension dos a lot,7.7 mil downloads.