In Google Docs you have the option to restrict Downloading, Printing & Copying in the sharing settings.
What is the benefit of this?
This is useful if you want users to be able to edit a document but you don't want them creating a copy of the document, or downloading it and printing it. It gives you more control over the documents you send.
How do I do this?
Step #1 - Click 'Share' in the top right of your Google Doc
In the top right of your Google Doc screen click the light blue 'Share' button.
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Step #2 - Open the further Share settings
Click on the settings cog in the top right of the share window.
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Tip #3 - Remove the option
Untick the box to disable the option for users to download, print or copy the doc.
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You can change these settings at any time, just follow the steps above.