Hi Carme,
yeah, you can they are free to use.
If you would like to see how other community members have used or created some check out this topic: Share your event printing materials
Also, you can see the text style guide on slides 50-51: https://docs.google.com/presentation/d/1fWz7XOtwKsAryKjxQOy52sH8VUUsiw3Xt5yKdwMIFfg/edit#slide=id.g5f041a7b0e_0_575
If you have any questions please free to ask.