This comes up in the Germany forum fairly often but applies here too, so here's a link to a very detailed description of the Bayern-Ticket for traveling between Salzburg and Bavaria (e.g., Munich)
The Bayern ticket is only one of numerous Lander ( State ) tickets available . If you are in Hesse or Saxony , for instance , Bahn provides information for all of them - https://www.bahn.com/en/offers/regional/regional-day-tickets
Steven - agreed. The Bahn site is pretty comprehensive and has come in handy as we are going to be in Alsace near the beginning of our trip and have considered side trips into Germany via Strasbourg. Same for our few days in Salzburg and day tripping out to Chiemsee.