Integration of Sharepoint online / 365 (File upload) in the React application hosted on Azure and WebApi C # .Net Core 2.2

I have been struggling for a few weeks trying to interact / automate a way to upload files from a web application created in React and upload files to a Sharepoint online site, in a specific folder. The web application is hosted on Azure and uses a C # .Net Core 2.2 as a backend.

I am trying to use some type of REST API to help me with this task (it could be in React in the interface, or in C # Core or C # MS FW .Net for the backend)
I'm searching the Internet for a way to do it, but all the tests failed.

Can anyone give me any ideas, advice or advice on how to achieve this?

I'm trying:

  • Use the code from the Microsoft website (using jQuery).

  • Using PnP, but on my local host I receive a CORS problem (I am trying to use client ID and secret ID to interact with Sharepoint).