It can be very tedious manually uploading documents to multiple libraries in SharePoint.  

There is a "Send To" function that makes this process much easier.

First, navigate to your SharePoint library that contains the document you would like to copy to another library and select that document.

Next, select "File" at the top of the screen and then select "Send To" and click on "Other Location"

In another tab, navigate to the library you will be copying this document to and copy the URL.

Paste the URL in the Destination field.  NOTE: Always test to see if you are linking to the right document.  If the link is sending you to the parent site, then remove the part of the link that is inbetween the parent site and the library.  ex. 

https://k2corp.sharepoint.com/Support/AppitSupportTeam/_layouts/15/start.aspx#/Shared%20Documents/Forms/AllItems.aspx

will in turn be turned into:

https://k2corp.sharepoint.com/Support/AppitSupportTeam/Shared%20Documents/Forms/AllItems.aspx

Finally, click next and then ok and your document will be copied over to the new library.