@leungi that's because:

"All materialized views are backed by a DLT pipeline. You can refresh materialized views manually, on a schedule, or by scheduling the DLT pipeline in which they’re contained."

At https://docs.databricks.com/en/sql/language-manual/sql-ref-syntax-ddl-create-materialized-view.html

In order to create Materialized Views, you need to use Delta Live Tables