BizTalk Server is used to connect between two systems. If you have one system as the source and another as the destination, it acts as a bridge. You can do transformations – the source system can send in a different format, and you can convert that schema into the destination schema. You can do transformation, and you can use orchestrations. There are a number of features in BizTalk.
We can use it for multiple purposes, mainly for messaging – to transfer messages from one location to another. We have various supports, send ports, receive ports, and other use cases as well. If you have conditions, you can use the Business Rules Engine (BRE). For tracking purposes, you can use Business Activity Monitoring (BAM).
There are so many databases involved because BizTalk stores all messages in the MessageBox DB, along with your Management DB and Tracking DB. In the Admin Portal, you can track messages.
If there are any failures due to network issues, okay, you can go to that step and resume the instance. From that step, it will continue. If the destination system is up, then it will go and create the record. You have so many adapters as well: File adapter, HTTP, basic web HTTP, SFTP, FTP adapter... the list goes on.