First, save your document to the desktop by clicking on File. Depending on your version of Word, your screen may look different. Also, there are other places to save it, but I have found this is the quickest way.
Click Save As.
Then, find the Desktop. In Word 2013 click Browse, in other versions of Word you should be able to find it by looking to the left of the screen (Like you see below).
Find your Desktop.
Then, click Save.
Your document will now appear on the desktop of this computer only when you are signed in.
Next, open OneDrive, find the file you want to save the document in, and click Upload. If you have IE 10 or above, you can drag and drop your documents from your desktop. Click here to watch the video.
If you are not using Drag and Drop, find your document (make sure you are looking on the desktop) and double click it.
Your document should now appear in your OneDrive.