In Standard version can I add a tag depending on the subject using Workflows?

In Standard version can I add a tag depending on the subject using Workflows?

Hi, 
I'm testing the standard version. 

I've found documentation on how to add tags using workflows (https://help.zoho.com/portal/en/kb/desk/automation/workflows/articles/custom-actions-gallery#Action_Failure_on_DeletingDeactivating_an_Agent) however the Add tags does not appear in the Standard version.

As an example if an email subject contains the word critical I would want a tag called critical added to that so that I can look at those technical tickets before the less critical ones.   

Please can you let me know if this is possible in the Standard version and if so, how I would do it. 

Thanks,
Karen