You can do it in many ways
1.
EXEC sp_MSForEachTable 'TRUNCATE TABLE ?'
but you cannot truncate tables which have foreign keys, so this will only work if there are no foreign key constraints between tables. You can disable constraint anyways.
2. use dynamic query if you know specific prefix of tables to truncate e.g emp_
SELECT 'TRUNCATE TABLE ' + TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'emp%'
this query will return Truncate statements of tables and then you can run these query at once. (again it will not truncate if having foreign key)
3. You can use cursor with dynamic query to select and truncate tables with above dynamic query.
Thanks