How to create or edit Apex classes or Apex Triggers

You can create, edit, and delete Apex classes and Apex triggers directly in the user interface only in Developer Edition, Sandbox, and Trial Org.

Additionally, to make changes to Apex classes or Apex triggers, you must assign the “Author Apex” permission to the user.

In production org, you can execute and view Apex classes from the user interface, but you cannot edit Apex classes or Apex triggers directly because the [Edit] button is not displayed on the user interface.

To modify Apex classes or Apex triggers in production org, use change sets, Salesforce CLI, metadata API.

• Change Sets
• Salesforce CLI
• Metadata API

[Note]

• When migrating Apex classes or Apex triggers to a production organization, you must create a test class and meet the minimum code coverage requirements.
• Apex classes and Apex triggers which is installed by managed packages cannot be edited or deleted.