The common currency of the euro means that the exchange bureaus can be hard to find in Germany (they're called Wechselstube or Geldwechsel in German), but they remain a common sight at airports and major train stations. It’s generally easiest to get your currency before you arrive. If you do need to exchange money in Germany, you can also do so at a bank. The Swiss Franc is accepted at some places near to the Swiss border.
Another option is to withdraw money from an ATM (called Geldautomat in german). They are ubiquitous in German cities and can be accessed 24/7. They are present at UBahn stations, grocery stores, airports, malls, shopping streets, train station, etc. They almost always have a language option so you can operate the machine in your native language. Before leaving for Germany, consult with your home back if they charge any fees.