Setting up OneSignal with Apple, requires 2fa for sign in but I have no apple device to get 2fa code

I think the title explains this as simple as possible.

I am setting up the certificate using the One Signal certificate wizard. How do I get my 2fa codes without having access to iOS device. I have an Apple ID from before getting my Android device, and it still works I am certain.

Any alternatives or do I have to borrow a friends phone or something and sign in to get this code.

Many thanks,

Eoin.