Good afternoon, 

I created an account on Booking website in order to rent my appartment. 

So as to proceed, I would like to know how I can write messages to customers prior their reservations in order to more details on their profiles and be sure to confirm or reject their bookings?

Then, I have another question, when I'm writing message on android app how can I have a confirmation that my answer has been sent? 

Last but not least, how can I put my android app into French language automatically instead of English?

Looking forward to hearing from you,

Best regards, 

Yves and Martine