Every car in Germany is required to have a regular safety inspection. This is commonly referred to as TÜV (short for Technischer Überwachungs-Verein) as they used to have the monopoly for car inspection in Germany.
The inspection is officially called HU (short for Haupt-Untersuchung). A new car needs to be inspected after 36 months and then every 24 months thereafter. You will receive a sticker (TÜV Plakette) on your license plate after a successful inspection. The number in the middle of the sticker will tell you the year when your car is due for the next inspection (e.g. 12 for 2021), the number on top of the sticker will tell you the month (e.g. 12 for December).
When you go for an inspection, make sure to have your car papers (Zulassungsbescheinigung Teil 1) with you, as the successful inspection will also be noted in your car papers.
You might also hear the term AU (short for Abgas-Untersuchung). This used to be a separate exhaust inspection which is now part of the HU.