Hello @Clare171,
Whether it's form 12 or 11 seems to depend on whether you're PAYE or self employed.
Going to the myAccount revenue site for PAYE workers and logging on I see that it refers to form 12 for the purposes of claiming credits or declaring additional income.
I used to be a PAYE worker but, since being made redundant, they now classify me as self employed so I must use the revenue ROS service. On that I use form 11 to declare Airbnb income.
Links to the two services are below.
myAccount
ROS - Log In
When first doing the reporting I went to the tax office in Limerick and was told to do it online.
I've found the ROS one effective but a bit labourious as it's really meant for businesses so it has lots of sections that don't apply to me.
The myAccount one for PAYE workers looks simpler. I'd suggest going to the tax office to see if they'll do it at the desk. You might get someone there who has nothing else to do as so many people do it online 🙂
Steve.