Custom Fields Permission Schemes

[Vika Mathieu]

How/where can I grant accesses/permissions to view, edit a custom field in JIRA?

[Victor Mutambuki]

Vika,

To start with, you'll need to be a jira admin to perform those tasks.

See link below on the topic. 
https://confluence.atlassian.com/adminjiraserver/adding-a-custom-field-938847222.html

Victor

[John Funk]

Hi Vika - Welcome to the Atlassian Community!

The ability to view or edit a custom field on a screen depends a lot on whether the field is actually on that particular screen. 

First, check the screen scheme being used for that project to see if the field shows up on any of the associated screens (Create, Edit, View).