CRM is used to manage and maintain customer relationships. The documentation of customer relationships is a strategic approach that includes the planning, control, and execution of all business processes with customers and thus enables in-depth relationship marketing. In many industries (e.g. mail order and service companies), business relationships with customers are oriented towards the long term. CRM is used to maintain these relationships in the long run. Customer data is managed and evaluated with the help of a CRM system. With the help of the customer data, targeted campaigns and actions can be controlled, e.g: Mailings to specific target groups. Customer data in connection with product data allow the generation of personalised catalogues, e.g. in case of shopping cart abandonment. These measures have a significant impact on the success of the company.