Headset will not be recognized Latitude 7480

You should have an option for just a regular Headset, but even if you have a non-Dell headset, you should still be able to use the "Dell Headset" profile.  Can you include a screenshot of the pop-up you're seeing?  That's an important step because that's how you tell the driver how to configure the audio jack properly for the type of device you plugged in.

I can't read the language but the headset should be just below the Blue Dell option.  The Left side for the headset/headphone and the right for small medium or large.

No sorry, in the menu headset/headphone there is only an option Headphone small, middle and big but I never can find the headset. Also the headset is not recognized in the windows device manager.

in the menu headset/headphone there is only an option Headphone

Hello. Google Translate says that "kopfhorer/sprechgarnitur" in English is "Headphones / Headset".  I would think that "sprech" (speak) refers to the mic part of the headset. That's the one you should use as Saltgrass said.

Also the headset is not recognized in the windows device manager.

Generally speaking, for an audio device to show up in Device Manager it should have a DAC (digital-to-analog converter) or an ADC (analog-to-digital converter) .

The integrated Realtek audio on the motherboard has them so it is seen as an audio device.

From the computer's point of view the headset jack socket is just an appendage of the Realtek device, and the headset is just an appendage of the jack. Headsets that do have a DAC/ADC, such as usb and Bluetooth types, will appear in Device Manager as devices.

I used the term "generally speaking" because there are exceptions when a device can actively identify itself as a device, often via a device driver, but most things plugged into the headset jack are detected, not identified, by a change in impedance.

If you just have a generic headset, you should see an option for that somewhere in the lower 2 rows.

kopfhorer/sprechgarnitur"

Those last 3 rows are completely separate from each other.  If you're not using any Dell Speakers, select one of the categories underneath that one and then select the appropriate item.  That's not a cumulative list where you have to pick one item from each row.  If you just have a generic headset, you should see an option for that somewhere in the lower 2 rows.

I had the same problem and solved them as follows:

• There is a "hidden trap" in this Dialog: "Kopfhörer/Sprechgarnitur" are TWO different options, where you have to select the right one. 
  The (really bad) user Interface seems to expect that  for your headphone you select "Kopfhörer" or "headphone", while for a headphone with mike you select just "Sprechgarnitur" or "Headset." So, the right part of the left column in the head... row should become blue.
  Then press OK. That way the mike worked for me.
• After upgrading to a new Version of the Audio Controller, there is an additional flag "diesen Dialog nicht erneut anzeigen" or "don't Show this Dialog again". With that you make the selection once and you are done.
  Have no clue, though, how to get the Dialog back, then...

So, upgrade the Driver, click on "Sprechgarnitur" and OK and it should work.