We have created Vf page to manage custom setting data , its working well for system admin but when we logged in as internal user it throws this error :system.security.NoAccessException: Create access denied for Operations_Email_Template_Mapping__c(Custom Setting). Is there way for internal users to manage custom settings data without granting them 'Customize Application' permission??
Normally, you'd simply update those settings in a "without sharing" utility class. Configuration pages are one of the few places where it might make sense to use "without sharing."
This is particularly true for hierarchy settings, where each user might set their own preferences. The typical use cases for list custom settings means you should probably restrict those types of custom settings just to system administrators.