In a SharePoint document library connector, you may optionally add Enterprise Keyword tags to the file when it is created in SharePoint. This option assumes that Enterprise Keywords are activated on your SharePoint instance. 

To activate Enterprise Metadata and Keywords Settings, navigate to your library's settings page, click the link for "Enterprise Metadata and Keywords Settings", then click the box for "Add an Enterprise Keywords column to this list and enable Keyword synchronization" and press OK. See below.

Next, navigate to your SharePoint document connector and add Keywords/Tags as shown below. Create a new keyword by pressing "add keyword" as these different fields will be separated by a ";" semicolon. Notice you can use the formula builder and/or any field in the form to be used for Metadata. Happy tagging! :)