Hello @stepanovxz and welcome to the community!
Create your dB structure
Contact
Name (text)
User (user)
Message
Title (text)
Comment (text)
User (user)
Confirmation code (text)
Create your UI
Create a page with dimensions for mobile and visibility flows so that add all necessary visual elements to display the data are done via one-page browser actions. This way you can wrap this page into a native mobile app through a wrapping service.
For the users contacts a repeating group should do the job
Create your workflows
- CRUD workflows for users contacts (create, read, update, delete). These take place in the workflows tab of the editor using events like when a button is clicked and actions like “create a new thing” or “make changes to a thing” should do the job.
- Create a signup workflow where one of the steps in “make changes to a thing” is to generate a random confirmation code like this:
- Entry by invitation is a more elaborate endeavour but easily doable with Bubble logic.
Hope the above provides a macro view of how to approach your project.
Best of luck! 