What is a Lead conversion process in Salesforce and what happens when a Lead gets converted?

When you qualify a lead, you can convert the lead record into an opportunity. You then work your opportunity until you close the deal by either completing it or canceling it.

When you convert leads, Salesforce creates accounts, contacts, and, opportunities using information from the leads you’re converting. If existing accounts and contacts share the names specified on the leads, you can choose to update the existing accounts and contacts. Salesforce adds information from the lead into empty fields; Salesforce does not overwrite existing account and contact data.