Interval partitioning is an enhancement to range partitioning in Oracle 11g and interval partitioning automatically creates time-based partitions as new data is added. ... For example, if a table was used to store sales data, it might be range partitioned by a DATE column, with each month in a different partition.

How do I add an interval partition to an existing table in Oracle?

You cannot partition an existing non-partitioned table. In general, you'll need to create a new partitioned table, move the data from the existing table to the new table (probably using a direct-path insert with parallel DML), drop the old table, and rename the new table to use the old name. You can do that manually.

How do I add a partition to an interval partitioned table?

You cannot explicitly add a partition to an interval-partitioned table. The database automatically creates a partition for an interval when data for that interval is inserted.