how to

Hello I am starting unity 2019 so what is the best way to create a c sharp script?

There are 2 ways which are most used:
1: go to inspector, add component and select script
2: or at the assets, right click, create, c# script then attach it to an object

Thank you, can you explain what is best utility to edit a script?

“Best” is hard for someone else to answer for you, but most people are happy with Visual Studio which comes bundled with Unity unless you tell it not to install. VS Code seems to have a good number of fans as well.