What are some good mobile apps that help in learning a foreign language?

Try Duolingo, it's fun ( Like a game) and you learn at the same time . 

Of course, it is much easier to find a decent tutor in a foreign language for yourself than constantly trying to use exercises in strange applications like duolingo. I recommend that you look for a tutor on the site where I found information about https://preply.com/en/blog/2019/02/15/how-to-learn-german/. I advise you to read this.

I used only the services of tutors. Therefore, I do not know mobile applications.

1. Duolingo

2. Babbel

3. Memrise

4. Ankiapp

5. Busuu

6. Mindsnacks

7. Brainscape

Some Mobile Apps that are helpful in learning foreign languages are :

1- Duolingo

2-  Google Translate

3- Fluenze

4- Babbel

5- Rosetta Stone

6- Bedidas