Making a mobile app is slightly different for every mobile application development company, but the general process stays the same. The process follows these steps:
Collect information from the client.
Develop a strategy to build the app including mockups and use plans.
Begin production while checking in with the client periodically to check that the project is on track.
Finish production and finalize the design.
Launch the app into the market.
Monitor performance and tweak the app as needed.
Some companies follow all of these steps while others do not. Check with any company that you plan to work with to see what their processes are before committing to the project.