How do I get an ID if I have a warrant?

You're effectively asking for advice on how to avoid arrest due to an outstanding warrant. Unfortunately, no attorney can ethically provide you that type of advice. As difficult as it may be, I would suggest trying to resolve the warrant. Otherwise, you're going to constantly run into situations where you have to find a way to elude authorities. Depending on what you do to evade the warrant and how zealous the prosecutor is, this could lead to additional charges being tacked on when it comes time to pay the piper.