Salesforce development involves customizing the Salesforce platform to meet specific business needs such as creating custom applications, automating processes, and integrating Salesforce with other tools. It is important for businesses as it allows them to optimize operations, enhance customer engagement, and gain valuable insights. Key Salesforce development services include customization and configuration, app development, integration services, and automation with workflows. These services provide benefits such as improved customer relationship management, enhanced data security, and increased efficiency and productivity.