Posting to Northern Ireland after 31st March

[mysterious_cities_of_mold]

Regarding the changes to postage for goods going to Northern Ireland from the rest of the UK from 31st March, I am a bit confused about what information I will need to give when sending a parcel. Do I need to supply a EORI number to Royal Mail when posting an item? On the Royal Mail click and drop website, there is also space to enter a "Recipient AIRN (UKIMS)" number? What other details are needed? I really don't want to stop selling to Northern Ireland but I am afraid that it will be too complicated.

[gemini-project]

It depends on a few factors, all the info is here https://www.royalmail.com/windsor-framework 

The last few items i have shipped to Northern Ireland have needed simple export forms to be filled in on the click and drop business website.

They required description of item, cost, weight, commodity code, country of manufacture, their EORI number if they are a business.

You might fall under C2C,

Parcels sent by a private individual in Great Britain to a private individual residing in Northern Ireland for personal use. Goods description, confirmation of goods categorisation by item (optional), weight (by item), value (by item).