I am not sure how to get rid of this vertical line? is it in the margin?
and when I click the Design Tab, the page is not in full screen
The line indicates a page break when printing. Your report is designed to print on paper that is either A2 or ANSI C in size, likely with landscape orientation.
First you need to determine what size paper this report is intended to use when printing. Then go to File > Page Setup in your Crystal Report designer and configure the Printer Options and Page Options. Printer Options should either be set to No Printer, or the printer that can print the paper size you plan to use. Page Options will define the paper size, orientation and margins.
If you plan to use a paper size that is smaller than 22 inches in width, you will need to reduce the size of the objects in your report to fit the size of the paper or allow it to span multiple pages.