Custom Attribute

[Harish Gollapali]

Dear Team,

I am new to Atlassian, can someone help to achieve below things:

Case:1=> Can we create a custom field/ attribute that stores the email address value of the users? If yes, kindly guide me the options and whole process.

Case:2=> Is there any way that we can update email option "who can see this"  from Only You and Admins to Anyone bulk wise?

When we use get method to see all the list of users using postman, we can only see the people whose permission set to anyone.