I'm not able to understand what is exactly Opportunity and Line Item in Salesforce.What is the difference between Opportunity and Opportunity Line item ?
Opportunity is kind of a pending deal which has an associated $ value with it. It represents that if the Opportunity can be closed successfully, then it will generate the $ amount of revenue for your company.
OpportunityLineItem are the Products which are associated to an Opportunity.
A company can have a number of products which it sells. All these products are generalized as Products. However, when a Product, or a number of Products are attached to an Opportunity, then they are called "OpportunityLineItem" records.
The $ value attached to an Opportunity comes from the Products associated with that particular opportunity as each Product (or OpportunityLineItem) has a $ value associated to it.
Please mark it an an answer if the above explanation was able to answer your question.
Opportunity : Use the Opportunity object to manage information about a sale or pending deal. Its like new or existing proposal that can turn into business.
Line item: : is every line that tells which products are involved in that opportunity