Sometimes download / export to pdf is a requirement of your Tableau dashboard. Whether it’s using the Tableau Server download button or downloading the pdf from Tableau Server using the URL the appearance is important. Components should fit cleanly on their page. For example splitting a chart across two pages isn’t particularly readable. Therefore the sizing of all components on the dashboard and the page set up is important.
Defining the number of pages is straightforward, simply by setting the Print Scaling. In Tableau desktop it’s found in File – Page Setup – Print Scaling.
Setting this to 1 page across and 2 pages down would mean it always exports to a pdf of 2 pages down and 1 across.
Sizing of components is a little more tricky. Fixing the dashboard size and fixing the size of containers within the dashboard is one way. Another alternative is traditional trial and error! Tableau will resize components on Download to PDF to fit to the selected paper size, always exporting to the number of pages defined in the Page Setup.