Tags are a way to organise your information to make it easier to find the thing you want, or for selecting sets of data for reporting.
Tags are the same across all modules, so you need to think about things that will be useful in more than one module. 

Common uses are for branch locations, business units, product lines, service categories, departments, or broad topics, like "Safety" or "Governance". You may also want to look at "Projects", since there is some crossover between Tags and Projects. 

Tags behave like an additional search parameter, and are shown at the top of each module.

Click on the tag to instantly filter the search results. 

You can apply multiple tags to your search to narrow your results, e.g., find documents that have both "Safety" and "Governance" tags. 

Don't plan on having a lot of tags as it won't work very well in a UI sense. All your tags show at the top of the other search options. When there are too many, it becomes crowded and hard to see the one you want. 

Don't worry too much about setting up tags when you're just beginning. You can always add tags and apply them to content as a bulk action later.

How to Create Tags

Go to settings via the gear icon in the top right. If you don't see it, then you don't have permission to change settings. 
Look for the "TOOLBOX" heading and click on 'tags'.

If you have some tags already, you'll see them listed. If you have a new system there may be none. Look for the "Add tag" button on the right. 

Enter your tag and click on "SAVE". If you want to add several, choose "Save and add another"

Edit a Tag

In the list of tags, click on the one you want to edit. Then change the name and click on "SAVE".
If you've applied this tag to content in the system, those items will still be linked to this tag, with its new value. e.g. I tagged a bunch of things with tag "safty", and then corrected the spelling of the tag to "safety". All my content that was tagged with "safty" is now tagged with "safety". 

Delete Tags

THERE IS NO UNDO. When you delete a Tag(s), it's gone. Any content that was linked to the deleted tag will no longer be linked. You can't delete a tag and then create a new one with the same name to restore the links. 

You can choose to delete a single tag using the red Delete button shown when you edit a tag (see above). There will be a confirmation screen that shows you any objects that are linked to this tag.

Deleting the tag does NOT delete your content. It will delete the tag and the links to your content. 

To delete multiple tags at once, select them from the list and then choose "Delete selected Tags" from the Action menu at the top. Then click "Go". You will be asked to confirm that it is what you want to do.