Page layout properties such as page size, page margins, and page orientation define how the report pages appear when previewed or printed. While a report's layout can be set for the whole report, you can also control the layout settings for each section of the report when your report contains multiple sections.
With the report section, e.g. "ReportSection1", selected in the Report Explorer the following Layout properties are available:
Margins are the space between the content of your report and the edge of the page. You can set the page margins using the Margins property of the page from the Properties panel. By default, the value of page margins (left, right, top, and bottom) is set to 1" or 2.5cm depending on your Windows regional settings.
You can change the default page size using the PageSize property of the page from the Property Grid and set it to the standard sizes such as Letter, Tabloid, Legal, Statement, Executive, A3, A4, A5, B4 (JIS), and B5 (JIS). You can also manually input the values in the Width and Height properties to customize the page size.
The Page or paper orientation is how the rectangular report page is oriented. While Portrait orientation is suitable for the text expanding in a vertical direction, Landscape orientation is suitable for horizontally expanding content like in Tablix data regions. You can specify the report page orientation using the PaperOrientation property of the page from the Properties panel. By default, the PaperOrientation property is set to Portrait.
To use different page orientations in the same output you would add a report section for each change in orientation e.g. ReportSection1 can be set to Portrait and ReportSection2 can be set to Landscape.