How to transfer id to a new computer if it's possible?

In advance sorry if this the wrong place to post this question.
Because you can no longer change the id you use in the launcher I'm unsure if I can use the same id on another computer.Also I use steam to play ff14 if that makes any difference.
Sorry if I sound rude or my question is confusing.

If you log into the same Steam account on the new computer, you should be able to use the same account as you had in the previous one

So just download the game using my steam account on the new computer and enter the same id?Phew I was really worried.Anything else I need to do?My freind metioned carrying data over I think...

Yes, just login via Steam on new computer.
But, you should export your System Configuration and Character Data via Character Screen first, or you will loose all your hotbar / gui settings etc.
Just click both of the two icons near you character name to upload each of these two, system settings and character settings to the ffxiv server, so you can later import them again.

The Square Enix ID once linked (required on Steam) is permanent (can be removed once by support) so as long as you use the same Steam account on a new or different PC, it will always load up that ID since it is attached to the Steam account itself.

Good morning! Thank you for posting in the Final Fantasy XIV Technical Support Forums.

We apologize for any inconvenience that has occurred when playing Final Fantasy XIV. Unfortunately, the issue you are describing does not appear to be a technical issue. I will go ahead and move this thread to “General Discussion" instead.

Thank you once again for visiting the Final Fantasy XIV Technical Support Forums!

Sorry.I can get confused where to post things.

I’ll add that you may have to reset your password the first time you log in from your new computer… I also have it through Steam, so that part worked fine, but sometimes SE gets finicky when you’re logging in on a new device. It gave me some sort of message that my account was locked and I panicked, but all it wanted was a password change and I was good to go.

there is also a way to transfer the hotbar setting and whatnot via the launcher. In the setting you go to back up and then you press backup again. It will give you a file that you can transfer to another computer. After that on the new computer you do the same thing but instead of doing backup again you click restore and upload the file you took before. :D hope that helps a bit