Yes, a motorway vignette is required for vehicles up to 3,500 kg when using Austrian motorways. You can buy a vignette at petrol stations, border crossings, the ANWB in the Netherlands or Touring in Belgium.
You can also buy a digital vignette in advance via the official ASFINAG website. Please note: The digital vignette must be purchased at least 18 days before departure due to consumer protection regulations.