Dear Mario Adrián R.
Welcome to the Microsoft community.
I understand that you seem to be using OneDrive on Android and need to create a favorite for better uploading as currently all files are uploaded to the same folder which tends to be confusing and very inconvenient.
If I have not misunderstood your question, you can refer to the following method. Please correct me if my understanding is wrong.
In OneDrive for Android (I'm using the latest version), you can create a folder and upload to it by the following method.



With the above methods, you can create different types of folders and categorize your documents for uploading.
It's worth mentioning that if you need to add Office documents to your phone's desktop, you can also download an Office app, such as Word, and then make the following settings in the app to add frequently used documents to your desktop for quick access.

I hope this is the result you were expecting, and please feel free to ask any questions you may have.
Sincere greetings,
Ian - MSFT | Microsoft Community Support Specialist