Hi Chezeatti29
Thank you for your message.
Even with a discount card for Austria (ÖBB Vorteilscard) you have to buy a ticket, as the ÖBB Vorteilscard is not a 100% discount. When booking, you can therefore enter your travel cards for Austria and Switzerland on SBB.ch or directly via ÖBB, for example, and book the corresponding ticket including seat reservation.
I wish you a pleasant afternoon. Best regards, FabianBl