Using the OneDrive website
Depending on the web browser you use, you can upload files up to 10 GB in size.
On the OneDrive website:
Browse to the location where you want to add the files.
Tap or click Upload.
You might be prompted to install Microsoft Silverlight. After you install it, you can:
Drag your files into the Drop files here area, staying on the page until they finish uploading, and you're done.
-or-
Tap or click select them from your computer.
Pick the files you want to upload, and then tap or click Open.