I have single page pdf document from Visualforce page using renderAsPdf, can we add multiple pages in the pdf document?
Thank you
To generate multiple paper pages out of one Visualforce page you could read up about CSS page-break-before: always;
. https://salesforce.stackexchange.com/a/194196/799 is a pretty decent example (shameless plug)
To generate 1 master PDF that combines content from multiple different Visualforce pages/components... Read up about apex:include, maybe apex:composition. Experiment with joining them up like that as simple html and use renderAs="pdf" when you're happy.