Dynamic document is an electronic document - bank statement. It is based on HTML, but can be viewed completely offline. It allows drill-downs, interactions, sorting and filtering of the data and more.
DS Reader is an application that allows viewing GMC Inspire Dynamic Documents on an iOS device. When you receive a dynamic document as an email attachment, you can use the DS Reader to open it. DS Reader also stores the documents once they were opened, so that you can get back to them any time.