Dear, sir
Nice to meet you.
I have read your post in carefully and it is very interested for me.
I have developed many mobile apps using android studio and X code for 6+ years and so have the rich experience in this space.
As a typical apps, I have developed the social networking apps such as taxi, traveling, chatting & dating, shopping, food ordering & delivery, game, media player and so on.
Of course, it is not so important and more important to accomplish it wonderfully so that you're satisfy about it.
I think design is very important because it is the first interface with user in the app.
If you accept my proposal, I need mock-up (workflow) or description about your project.
Again, I will accomplish it better than another freelancers.
Please believe about this point.
If you may award me, I'll provide good quality in time.
I always satisfy all of your requirement and will be faithful to your project.
I value my credit and always will be kept the promise with you.
Please invite me on chat and give me a chance to serve you.
Finally, I'd like to work for your app with you and I'll do my best for you.
Looking forward to hear from you.
Thanks looking for my proposal.
Best regards