How to find all trigger associated with a table with SQL Server?

You can do this simply with SSMS. Just go to your table name and expand the Triggers node to view a list of triggers associated with that table. Right click to modify your trigger.

select so.name, text
from sysobjects so, syscomments sc
where type = 'TR'
and so.id = sc.id
and text like '%YourTableName%'

This way you can list out all the triggers associated with the given table.

This might be useful

SELECT 
 t.name AS TableName,
 tr.name AS TriggerName  
FROM sys.triggers tr
INNER JOIN sys.tables t ON t.object_id = tr.parent_id
WHERE 
t.name in ('TABLE_NAME(S)_GOES_HERE');

This way you just have to plugin the name of tables and the query will fetch all the triggers you need

select m.definition from sys.all_sql_modules m inner join  sys.triggers t
on m.object_id = t.object_id 

Here just copy the definition and alter the trigger.

Else you can just goto SSMS and Expand the your DB and under Programmability expand Database Triggeres then right click on the specific trigger and click modify there also you can change.