Does a Steel Roof Covering Required an Underlayment?

https://hectorahzi810.edublogs.org/2020/04/06/12-things-to-know-about-steel-roofing/

It's consequently that Beartooth Metal Roof covering in Invoicings always tears off the old roof shingles prior to using a new roof covering. I've done several roofing systems on patios and outbuildings on my farm