Building on what Fran said, there are a couple of ways you can accomplish this. In the “Customers” table, there is the field “CreatedDate”. You can add this field to any grid based on the “Customer” table to be able to filter by dates. The grid on the “CRM_CustomerList” screen is actually based on the “Contacts” table. In the “Contacts” table you will use the “EntityCreatedDate” field instead.
You can also add a filter rule to the grid which will only show the customers within the date range specified in the filter. This is good if you are often searching within the same range of dates as it will allow you to simply click the filter from a dropdown list instead of having to type in your search as well as allow you to add multiple filters. If you are interested in filtering using the current date as a rule, see my post here for more information on how to accomplish that.