OneDrive sharing from the File Explorer

Navigate to a file or folder stored inside OneDrive, and once there, right click the file or folder. The following context menu should pop up, showing options for OneDrive as marked in the image below.

Right Click context pane in File Explorer

When you click on the "Share" or "Manage Access" link, the following image will populate. If you choose "Copy Link" it will generate a link with edit access for everyone who has the link and will copy it to the clipboard automatically.
 

Share Page for OneDrive context menu

This menu allows you to add people to have access to the document, what level of access they have, and add a message. When you hit "Send" it will send them an invitation via email to either Edit or View depending on the access you granted.