Hi Naaman,
You can upload your documents to SharePoint Online sites to store them in the cloud. Please follow the steps below to upload files to a library:
1. Assign SharePoint Online service license to the account, and then give it proper permissions:
office.microsoft.com/.../step-2-plan-sites-and-manage-users-HA102044898.aspx
2. Access SharePoint team site, click Shared Documents or create a new library with a name that you specify:
office.microsoft.com/.../create-or-delete-a-library-HA101964718.aspx
3. Upload files to a library.
office.microsoft.com/.../upload-create-or-delete-files-in-a-library-HA102803549.aspx
Thanks,
Nancy Xie