Do you want to practice German on your own? The language section of the app "Ankommen" is a good way to do so. You will learn the language quickest by speaking to Germans. You do not have to be afraid of making mistakes. Most Germans know how difficult it is to learn a language and are happy that you are making such an effort.
Practice, practice, practice
Your conversation partner may even suggest changing to a different language. Lots of people can speak foreign languages such as English, French and Spanish. This is meant as a friendly offer. If you want to improve your German, however, you should ask your conversation partner to speak German slowly and with simple words.
You can find more free online opportunities to learn German here:
Goethe-Institut learning pages and apps
German learning portal from the Deutscher Volkshochschul-Verband (German Adult Education Association) „Ich-will-deutsch-lernen“ (“I want to learn German”)
Online courses from Deutsche Welle (German public broadcaster)