After you install it, you can use:
pack <- "name_of_your_package"path <- find.package(pack)system(paste(shQuote(file.path(R.home("bin"), "R")), "CMD", "Rd2pdf", shQuote(path)))
There is
devtools::build_manual()
Maybe also
devtools::check(manual=TRUE)
could work.
For the PDF manual of one specific function, you can run
fun <- "name_of_function"help(fun, package = "name_of_package", help_type = "pdf")system(paste0("open ", fun, ".pdf"))
assuming you have the package installed.