Hi, @Velmurugan Thanks for the ask and for using the Microsoft Q&A platform.
As we understand the ask here Migrate Oracle to Azure Database for PostgreSQL(PAAS) using DMS.
That scenario isn't supported anymore please check this documentation for the supported scenarios
If you can afford unavailability of the system for the data migration, the best bet is ora2pg. ora2pg also has a data migration capability. You can use it to move data from Oracle to PostgreSQL.
Please let us know if the information is helpful.