Manage licence for my app

please how can i make a licence for my app to sell it under licence

What specifically do you mean by this? What exactly are you trying to achieve?

If you’re looking for a way to distribute your code without someone being able to copy or use it without your permission, don’t bother trying. You’re going to spend far more time and money trying to do that than you will make as income.

Otherwise, you can assign any license you wish to your code, provided you adhere to all the licensing requirements of every library and module that you package and distribute with your code.

thanks for your answer,
so i developed an app and I need to sell it to my clients, so i have to make a licence for my app for each client to avoid coping my app to other clients
so how to secure my app for each client ??

You don’t. (Or perhaps more accurately, you can’t effectively do that.) Python (among a couple of other languages) isn’t conducive to that sort of protection.

humm, so there is no way to secure my app ?

Answering this for the third time, no. Not in the way you describe.