I am building a small R package that will render an rmarkdown document, however, I don't know where to save my rmd so that it can be ran and displayed from a function inside the package. I got this small function below:

#' @title shiny app to print automated document
#' @import shiny rmarkdown utils
#' @return shiny app for documents. Type 'doc()' to launch doc.
#' @name doc
#' @examples
#' doc()
#' browseURL("sample.pdf")
#'
#' @export
#'
doc <- function() {
  library(shiny)
  library(rmarkdown)
  rmarkdown::render("sample.rmd"),
                    output_file = "sample.pdf")

}

The sample.rmd file is:

---
title: "sample"
output: pdf_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## R Markdown

This is an R Markdown document.

I don't want to use system.file() as input inside render because I want the output to be saved on a file within my project directory and not under the R library directory. Let me know if is not clear and I can elaborate a bit more.