The MongoDB store the data in documents with JSON format but SQL store the data in Table format.
The MongoDB provides high performance, high availability, easy scalability etc. rather than SQL Server.
MongoDB mentioned to document-based NoSQL databases but SQL Server mentioned to relational database.
MongoDB is a NoSQL database so there's nothing like a stored procedure. You can create a set of common functionality in a class library.
The "fire-and-forget" is a default option to check query operations but we can use to "getLastError" method to check query operations succeeded or not.
In the MongoDB, we can change the structure simply by adding, removing column from the existing documents.
For SQL Server to MongoDB mapping chart, go to live link https://docs.mongodb.org/manual/reference/sql-comparison/
For more detail, go to below link.