Change name issues - personal name to business name

Hello, I read on the Self Assessment FAQ page that I can change my Self employed name. Right now my self employed name is name and surname. I would like to add another word. When I log into the 'profile and setting' page of the account home I am just given TITLE, NAME and SURNAME options to change. Should I add the business name after the title? i.e. Name: John Surname: Smith t/a ABC I really don't understand how to change the name. Many thanks.

Hi
Yes if you have a trading name then you can update the record with the details of your name and trading name. You can also contact HMRC to review and update. You can contact HMRC at Self Assessment: general enquiries

I have exactly the same question as Angela Caretta above. Where/how do I add a trading name. It won't allow me to add in the Surname section. Please help

Hi,
You can update your trading name here:
Tell HMRC about a change to your business
Thank you.