diff --git a/R/add_header_above.R b/R/add_header_above.R
index 4c83a8e..baba605 100644
--- a/R/add_header_above.R
+++ b/R/add_header_above.R
@@ -1,4 +1,17 @@
-#' Add an extra header row above the current header
+#' Add a header row on top of current header
+#'
+#' @description Tables with multiple rows of header rows are extremely useful
+#' to demonstrate grouped data. This function takes the output of a `kable()`
+#' function and adds an header row on top of it. This function can work with
+#' both `HTML` and `LaTeX` outputs
+#'
+#' @param kable_input Output of `knitr::kable()` with `format` specified
+#' @param header A (named) character vector with `colspan` as values. For
+#' example, `c(" " = 1, "title" = 2)` can be used to create a new header row
+#' for a 3-column table with "title" spanning across column 2 and 3. For
+#' convenience, when `colspan` equals to 1, users can drop the ` = 1` part.
+#' As a result, `c(" ", "title" = 2)` is the same as `c(" " = 1, "title" = 2)`.
+#'
 #' @export
 add_header_above <- function(kable_input, header = NULL) {
   kable_format <- attr(kable_input, "format")