Moving one file into multiple folders is a hidden feature of Google Drive. It's a bit of a paradigm shift because unlike paper you are not putting your files in actual folders in a filing cabinet. You are actually giving it a label disguised as a folder icon. The document is NOT copied when it is in multiple folders. It is the same document with multiple labels.
Move to a Folder
Click once on a file to select the file in Google Drive. The more icon looks like 3 dots along the top of the files. It is located next to the trash can icon. Selecting the more icon gives you the option to move the file into a folder.
Choose the folder you want to move the file into.
Go to the Folder
Find the file you just moved to the folder. Select the file by clicking on it.
Hold down the shift key and strike the Z key. Notice you are now given the option to "Add to" instead of move. You an add the file to a second folder. Repeat with shift Z to add to additional folders.