i need mobile app

I want an application consisting of 2 pages. First page will be “log-in page”. On this page, a special code which is provided by only me, will be requested from the user. User can open and use the application after entering this code. For instance, 100 users can log in by using
the same code (I want to follow the number of people using and entering my application).
On the second page, there will be a single home page. Small and round images will be placed side by side (Just like the image I attached. When the image is clicked/touched, there will be a content just like the one that I also attached. So, these are the things that I want. How much is that going to cost ,and when can you deliver this? Thank you in advance!



Do you actually need a mobile app or would it be enough to use a web app or responsive website?

it could be