Hi Shravya,
SBO offers two different techniques for this requirement. Both have to be licensed.
First is the integration framework ( B1iF ) http://scn.sap.com/community/business-one-integration-technology which basically is a server software that enables you to do all kind of interaction/integration with SBO. It is Apache Tomcat based and you use a web frontend to define/configure your scenarios.
The business logic itself is pure XML ( XSLT ). In your case you would define a Webservice which receives a XML and transforms it into SBO Sales Order structure -> add to SBO.
Imho it needs a lot of learning and/or abilities to start from scratch. For me as a developer the debuging features / problematic configurations are too time consuming. Once you are familiar it is a powerfull tool.
The other technique is SBO DI Server ( + B1WS ). It is a soap based server software which allows you to manipulate SBO objects. It is designed for heavy duty operations and apart from some problems every now and then, it is a a reliable and fast tool. In addition you can use B1WS to offer WSDL files for DIS which you can use easily in different developing environments.
If you ask me: Get a DI Server + B1WS, create a ( secure ) Webservice to receive data from your APP. Write some lines of code to add sales order, done.
regards,
Maik