OAC users are managed via the Identity Cloud Service (IDCS), You need to use that to change your password or ask your administrator. https://docs.oracle.com/en/cloud/get-started/subscriptions-cloud/csgsg/manage-your-passwords.html

As I understand it from this support note, it is an issue with the Chrome PDF plugin and therefore not possible.

What are you viewing it with? What error do you get. I cannot read the SNAG files you keep referencing. Have you tried renaming the file to .pdf so Adobe knows what it is?

Are you using pre-view mode? If so turn this off using Chrome => Settings => Content settings => PDF documents => Enable 'Download PDF files instead of automatically opening them in Chrome' 

As per the OAC documentation whilst Azure SQL Server is a supported data source Azure SQL datawarehouse (Synapse) is not.

There are 2 OAC flavors. The main OAC uses a version of the Oracle BIEE server as its backend engine. This allows one to define a repository that pulls data from multiple data sources. If a data source in turn has analytical capabilities, the BI server might push some of the analysis to the data source. One of the possible…