diff --git a/R/add_header_left.R b/R/add_header_left.R
index 97336e5..ba713a1 100644
--- a/R/add_header_left.R
+++ b/R/add_header_left.R
@@ -1,6 +1,23 @@
-#' Add a header column
+#' Add a heading column to the left side of the table
 #'
-#' @description Experimenting. Please don't use it in production
+#' @description This function uses the same syntax as add_header_above. It will
+#' add a heading column with grouped rows to the left side of the table. It can
+#' act as an alternative way to `group_rows` to show grouped information. As
+#' `add_header_above`, users can use this function to add multiple layers of
+#' heading columns one by one.
+#'
+#' @param kable_input Output of `knitr::kable()` with `format` specified
+#' @param header A (named) character vector with `rowspan` as values. For
+#' example, `c("xxx" = 1, "title" = 2)` can be used to create a new header column
+#' for a 3-row table with "xxx" spanning row 1 and "title" spanning row 2 & 3 (
+#' two rows). For convenience, when `rowspan` equals to 1, users can drop the
+#' ` = 1` part. As a result, `c("xxx", "title" = 2)` is the same as
+#' `c("xxx" = 1, "title" = 2)`.
+#' @param header_name Column name that that extra column
+#' @param align Column alignment. you can choose from "c", "l" or "r"
+#' @param ... extra variables for latex or html. For LaTeX table, you can have
+#' a TRUE/FALSE option `full_midline` to control if the mid line needs to be
+#' extended to the end of row.
 #'
 #' @export
 add_header_left <- function(kable_input, header = NULL, header_name = "",