How-To Question: Can I Automate Ticket Tagging Based on Keywords?

I'm looking for a way to automate the process of tagging tickets based on keywords in the ticket subject or body. For example, if a ticket contains the word 'refund', I want it to be automatically tagged with 'refund_request'. Is this possible to do with the built-in automation features, or would I need to use a third-party integration? I've looked at the trigger and automation rules, but I can't seem to find a way to do this. Any guidance or examples would be greatly appreciated. Automating this process would save us a lot of time and would help us better categorize and prioritize our tickets.