Hi, @Apil Tiwari Welcome to Microsoft Q&A, Thanks for posting your query.
As we understand you want to know how to export Postgres DB from Azure Postgres flex.
You can achieve this by using pg_dump/pg_restore however can you please confirm if you are trying to export from flex to another in azure? or single to flex?
please refer to this document for more information on pg_dump/pg_restore.
Regards
Geetha