Hello Dhruvin,
That is a very complex topic. In general a sales area relates to a part of your organization. It is the combination of sales organization (= org unit), division (= product area) and distribution channel (= way of trade). So you can store information which is sales area specific. E.g. payment conditions might differ from sales area to sales area in the SAP database concept. There is much more to this topic. One could write a whole book about it and I think this is too much for a SCN thread.
Best regards,
Thomas Wagner