Display email on the user profile

When posting an ad, there is an option to specify whether or not the user's email address should be displayed. If "yes" is selected, this email should also appear on the user's profile—but how can this be done?
Also, is there any other easy way for the user to choose whether or not the email address used for registration appears on their profile?

Osclas does not have such option, email is usually not shown due to spam risk

And if I want to do it, how is it possible?

- add new column to user table (b_show_email, b_show_phone)
- user_edit/edited/_completed hooks to propagate changes to db
- get value from db and update theme
- add checkbox to user form so user can choose

Following your instructions, the issue was resolved; now, if the user wishes, their email appears on their profile.