indexing - primary key and index concept -

I create a column as the primary key, does it automatically index? Or do I need to explicitly create indexes? I was under the impression that the primary key also keeps indexed.

Creating a primary key in SQL Server is a unique The cluster index on that column or more specifically

Note The primary key constraints are automatically generated by package indexes if a package index does not already exist on the table and when you create a primary key constraint So a nonclustered index Is not specified.