What is the difference between a customer relationship management (CRM) system and a customer portal

Customer relationship management (CRM) suggests a more sophisticated system with more options for sales and marketing. CRM systems allow users to schedule upcoming actions, events, and meetings, move prospects through the sales funnel, generate email lists, and categorize prospects and customers. It does more than just store data; they also manage relationships, sales cycles, and funnels.

Source: https://www.elatesoft.com/blog/customer-relationship-management/