diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
index b3aeda852a..a9186ba514 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala
@@ -596,6 +596,12 @@ case class WeekOfYear(child: Expression) extends UnaryExpression with ImplicitCa
 // scalastyle:off line.size.limit
 @ExpressionDescription(
   usage = "_FUNC_(timestamp, fmt) - Converts `timestamp` to a value of string in the format specified by the date format `fmt`.",
+  arguments = """
+    Arguments:
+      * timestamp - A date/timestamp or string to be converted to the given format.
+      * fmt - Date/time format pattern to follow. See `java.time.format.DateTimeFormatter` for valid date
+              and time format patterns.
+  """,
   examples = """
     Examples:
       > SELECT _FUNC_('2016-04-08', 'y');
@@ -654,7 +660,14 @@ case class DateFormatClass(left: Expression, right: Expression, timeZoneId: Opti
  * Deterministic version of [[UnixTimestamp]], must have at least one parameter.
  */
 @ExpressionDescription(
-  usage = "_FUNC_(expr[, pattern]) - Returns the UNIX timestamp of the given time.",
+  usage = "_FUNC_(timeExp[, format]) - Returns the UNIX timestamp of the given time.",
+  arguments = """
+    Arguments:
+      * timeExp - A date/timestamp or string which is returned as a UNIX timestamp.
+      * format - Date/time format pattern to follow. Ignored if `timeExp` is not a string.
+                 Default value is "uuuu-MM-dd HH:mm:ss". See `java.time.format.DateTimeFormatter`
+                 for valid date and time format patterns.
+  """,
   examples = """
     Examples:
       > SELECT _FUNC_('2016-04-08', 'yyyy-MM-dd');
@@ -692,7 +705,14 @@ case class ToUnixTimestamp(
  * second parameter.
  */
 @ExpressionDescription(
-  usage = "_FUNC_([expr[, pattern]]) - Returns the UNIX timestamp of current or specified time.",
+  usage = "_FUNC_([timeExp[, format]]) - Returns the UNIX timestamp of current or specified time.",
+  arguments = """
+    Arguments:
+      * timeExp - A date/timestamp or string. If not provided, this defaults to current time.
+      * format - Date/time format pattern to follow. Ignored if `timeExp` is not a string.
+                 Default value is "uuuu-MM-dd HH:mm:ss". See `java.time.format.DateTimeFormatter`
+                 for valid date and time format patterns.
+  """,
   examples = """
     Examples:
       > SELECT _FUNC_();
@@ -866,6 +886,12 @@ abstract class UnixTime extends ToTimestamp {
  */
 @ExpressionDescription(
   usage = "_FUNC_(unix_time, format) - Returns `unix_time` in the specified `format`.",
+  arguments = """
+    Arguments:
+      * unix_time - UNIX Timestamp to be converted to the provided format.
+      * format - Date/time format pattern to follow. See `java.time.format.DateTimeFormatter`
+                 for valid date and time format patterns.
+  """,
   examples = """
     Examples:
       > SELECT _FUNC_(0, 'yyyy-MM-dd HH:mm:ss');
@@ -1408,6 +1434,12 @@ case class ToUTCTimestamp(left: Expression, right: Expression)
       a date. Returns null with invalid input. By default, it follows casting rules to a date if
       the `fmt` is omitted.
   """,
+  arguments = """
+    Arguments:
+      * date_str - A string to be parsed to date.
+      * fmt - Date format pattern to follow. See `java.time.format.DateTimeFormatter` for valid
+              date and time format patterns.
+  """,
   examples = """
     Examples:
       > SELECT _FUNC_('2009-07-30 04:17:52');
@@ -1446,10 +1478,16 @@ case class ParseToDate(left: Expression, format: Option[Expression], child: Expr
  */
 @ExpressionDescription(
   usage = """
-    _FUNC_(timestamp[, fmt]) - Parses the `timestamp` expression with the `fmt` expression to
-      a timestamp. Returns null with invalid input. By default, it follows casting rules to
+    _FUNC_(timestamp_str[, fmt]) - Parses the `timestamp_str` expression with the `fmt` expression
+      to a timestamp. Returns null with invalid input. By default, it follows casting rules to
       a timestamp if the `fmt` is omitted.
   """,
+  arguments = """
+    Arguments:
+      * timestamp_str - A string to be parsed to timestamp.
+      * fmt - Timestamp format pattern to follow. See `java.time.format.DateTimeFormatter` for valid
+              date and time format patterns.
+  """,
   examples = """
     Examples:
       > SELECT _FUNC_('2016-12-31 00:12:00');