I have a logged in user to the azure's active directory, is that possible to use the token i have to connect to SharePoint to upload some files instead of using the username and password?
This is for SharePoint 365
I believe you can do this using the Microsoft Graph API as you'd be using the users access token. I don't really recommend it as there's usually other ways to do what you need.
Side note: If you mean spoof the user in question then no, I don't believe so. I think you can generate a special type of password to access the SharePoint API using Azure but I don't know much about it personally.
Extra side note: It'd probably be easier just to upload the files to SharePoint and adjust the Created/Modified columns to the user.