Hey there @Emmytender,
Nice to hear from you again!
The BMI or BAMF explain everything you need to know about German naturalization/ getting the German citizenship on the following websites:
(The BMI site is in German, but it includes further information regarding the language level you need to have).
Let's have a closer look at the requirements (BAMF source):
- you have an unrestricted right of residence at the time of being naturalised,
- you have passed the naturalisation test (knowledge of the legal and social system, as well as living conditions in Germany),
- your habitual, lawful place of residence has been in Germany for eight years (this period can be reduced to seven years if you attend an integration course successfully, and can be reduced to as few as six years in the case of special integration measures),
- you have independent means of securing a living (including for family members entitled to maintenance) without resorting to welfare payments and unemployment benefit II,
- you have adequate German-language skills,
- you do not have any convictions on account of a criminal offence,
- you are committed to the free democratic constitutional order of the Basic Law of the Federal Republic of Germany, and
- you have lost or given up your former nationality (exceptions apply with regard to this point, depending on the country of origin; please contact the naturalisation authority).
Here are also some threads from our platform discussing your question: When can I get German citizenship?
Can I apply for citizenship after having an Aufenthaltserlaubnis for 3 years?
I've had another look regarding dual citizenship and found this information from the BMI in English: https://www.bmi.bund.de/SharedDocs/faqs/EN/themen/migration/staatsang/Doppelte_Staatsangehoerigkeit_Mehrstaatigkeit_en.html
Let me know if you need any further assistance, I hope the sources I linked here help :-)
All the best,