Uploading Files or Folders in SharePoint
Upload File/Folder to SharePoint Document Library by “Drag and Drop”
The simplest and most common way to upload image to SharePoint or upload document to SharePoint is the “drag and drop” method. You can use this method to upload files and folders to SharePoint from your computer.
Step 1. Log in to your SharePoint and open a document library on your SharePoint site.
Step 2. Open the Windows File Explorer on your computer and find the files that you want to upload to your SharePoint library.
Step 3. Drag the files and drop them to the document library of a SharePoint site.
How to Upload to SharePoint by “Upload” Button
The most basic and intuitive option for uploading files on SharePoint is to use the "Upload" button displayed on the Documents library.
Step 1. Open a document library of a SharePoint site.
Step 2. Click the "Upload" button above and choose "Files" or "Folder" in the dropdown list.
Step 3. Navigate to your files in the pop-up window and click "Open"
Provided via: https://www.multcloud.com/tutorials/upload-file-to-sharepoint.html