Thank you for reaching out to the Community. That is a great question! I would recommend saving a Master Template that you can reuse at your convenience, whether that's in an Autoresponder or an email campaign.
The steps I have attached above start at the beginning of creating a new template. If you already have it, you can simply save a copy and rename it Master Template.
Once you have your draft saved, you can copy the template to use in future campaigns, leaving the original saved in your account going forward. I hope this helps! In the meantime, if you have any further questions please feel free to reach out to us here. We are always happy to assist you in any way we can!