I bought 2 tic for tonight's twenty one pilots show. Got them thru flash seats. Tickets are a scan code on the phone. Wil that work? Because i don't see a way to print them out.

Yes. They can/will scan your phone. You'll need the flash app and you'll be ok.

As long as you have the app you're good to go. If not, head to the box office with the reference code.

Yes download Flash Seat app and show them the barcode https://www.flashseats.com/Mobile.htm

I used a barcode scan on Monday via my phone with no issues.