Regarding transferring money.

Hello I was gifted quite a bit of money from someone in the US therefor I set up an offshore account in the US which the money was then deposited in to.

i want to transfer the money from my off shore account in the US to my UK bank account (I’m from the UK and have never been to the US), but every-time I go to transfer the money I put the relevant details in and then the code to authorise the transaction which is all fine but then it asks me to put an IRS code in right at the end but I don’t have an SSN or an ITIN.

do I need to apply with the IRS to be able to transfer the money in my US bank account to my UK account?

thank you in advance.