Good Day Ma'am/Sir,
I would like to let you know that I'm a very hardworking and dedicated person. I'll do my work with full honesty. As I am a freelancer in this sector, I have much working experience.
But I do have the qualities that make me good at this work. I want to help you in promoting your app
So, if you hire me, I'll do my best to complete your work perfectly. And give you the best output you have ever seen.
If you want, you can contact me through email, Skype and Whatsapp and any kind of communication methods. I'm eagerly waiting for your response.
Yours sincerely
Jessica