I want to delete and modify previously created triggers but i cant find them anywhere in database. Where they exist and how to edit or delele them
You can also find the triggers by querying the management views in SQL Server Management Studio:
SELECT
OBJECT_NAME(object_id) 'Table name', *
FROM
sys.triggers
That gives you a list of all triggers and what table they're defined on for your current database. You can then go on to either disable or drop them.