I searched around I found that there are ways to transfer/sync data from sql-server to mongodb.
I also know that Mongodb contains collections instead of table and the data is stored differently.
I want to know whether it is possible to move data from mongodb to sql-server. If yes, then how and what are the tools/topics should I use?
Of course it’s possible, but you will need to find a way to force the flexibility of a document db like MongoDB into a RDBMS like SQL Server.
It means that you need to define how you want to handle missing fields (will it be a NULL in the db column? or a default value?) and other things that usually don’t fit well in a relational database.
Said do, you can use an ETL tool able to connect to both databases, SSIS can be an example if you want to stay in the MicroSoft world (you can check this Importing MongoDB Data Using SSIS 2012 to have an idea) or you can go for an open source tool like Talend Big Data Integration which has a connector to MongoDB (and of course to SQL Server).