How to create a Script from another Script on runtime

I want to create a script or import a script from outside the game on runtime. But without using the AssetBundle. Thank you in advance.

What you are asking about I think is run-time scripting.

There is no simple answer for that. I suggest you google “Unity runtime scripting” and look through all the various discussions.

What I do is that I have created a scripting framework with code in UnityScript that I process using eval()