Hi! Some time ago I used with great satisfaction the addon “Send and archive”, which simply added an extra sending option that automatically archived the email you were replying to. Unfortunately, after a Thunderbird update the addon doesn’t work anymore. I strongly suggest that this addon be updated or an equivalent one created. Better still, I think such a useful option (it really changes your life in working towards avoiding inbox clutter) should be a standard Thunderbird button. Thank you for any information and help on this!
Will this one work for you?
If not the one you used should have a developers support site or information on the extensions page. You need to contact them.