Start with your document open. Click Insert from the menu bar across the top.

This will insert a table that you can use as a border. Drag the bottom of the border to drag it to fill up your entire page.

You can also add a border around individual paragraphs.

Highlight your paragraph and click "Format"

Google Docs is a cloud-based document editing and collaboration platform. Learn how to change your doc margins, delete pages from docs, strikethrough text, and much more.

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Adding a border in Google Docs is easy and can be accomplished in a few different ways. Oddly enough, there isn't a tool to simple insert a border around your margins. The most common ways are to use a table, add a picture, or use borders around individual paragraphs.

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