You can delete custom fields using Schema Builder.
|Available in: both Salesforce Classic and Lightning Experience|
|Available in: All Editions|
|To delete custom fields in Schema Builder:||"Customize Application"|
Schema Builder displays a list of side effects when you try to delete a custom field. Be sure you’re ready to accept these side effects before finalizing the deletion.
- Right click on the custom field.
- Select Delete Field.... A dialog box displays that explains the side effects of deleting a custom field. Read this information carefully.
- If you accept the conditions, check Yes, I want to delete the custom field.
- Click Delete.