Salesforce is used by a lot of companies as it is one of the biggest CRM tools on the market still today. Companies like Staples Corporate use this program to manages the company’s relationship with its customers. In other words, the CRM (Customer Relationship Management) is a tool through which the company and its employees can analyze the customer interactions, churn rate, buying patterns by maintaining a database.
One thing I will say is that it is expensive when buying licenses and is not for a beginner getting to CRM. An alternative option that is more "user friendly" would be https://www.thryv.com - No other software integrates payments, marketing and CRM tools like Thryv.
salesforce is probably the dominant player in the CRM game. What they do is simply automate and organize your custromer management, as well as capable of generating leads using based input. Pretty much a need, if you're atleast a medium sized company and youre running important business to business relations