diff --git a/src/Functions/array/indexOfAssumeSorted.cpp b/src/Functions/array/indexOfAssumeSorted.cpp
index 0a43eca8739..c4aeec665dd 100644
--- a/src/Functions/array/indexOfAssumeSorted.cpp
+++ b/src/Functions/array/indexOfAssumeSorted.cpp
@@ -1,6 +1,7 @@
 #include "arrayIndex.h"
 #include <Functions/FunctionFactory.h>
 #include <Functions/IFunctionAdaptors.h>
+#include "Common/FunctionDocumentation.h"
 
 namespace DB
 {
@@ -10,5 +11,18 @@ struct NameIndexOfAssumeSorted { static constexpr auto name = "indexOfAssumeSort
 /// should be used when the array is sorted (applies binary search to array)
 using FunctionIndexOfAssumeSorted = FunctionArrayIndex<IndexOfAssumeSorted, NameIndexOfAssumeSorted>;
 
-REGISTER_FUNCTION(IndexOfAssumeSorted) { factory.registerFunction<FunctionIndexOfAssumeSorted>(); }
+REGISTER_FUNCTION(IndexOfAssumeSorted)
+{
+    factory.registerFunction<FunctionIndexOfAssumeSorted>(FunctionDocumentation{
+        .description = R"(
+The function finds the position of the first occurrence of element X in the array.
+Indexing from one.
+The function can be used when the internal array type is not Nullable and the array is sorted in non-decreasing order.
+If the array type is Nullable, the 'indexOf' function will be used.
+The binary search algorithm is used for the search.
+For more details, see [https://en.wikipedia.org/wiki/Binary_search]
+For an unsorted array, the behavior is undefined.
+)",
+        .examples = {{.name = "", .query = "SELECT indexOfAssumeSorted([1, 2, 2, 2, 3, 3, 3, 4], 3) FROM test_table;"}}});
+}
 }
diff --git a/tests/queries/0_stateless/02415_all_new_functions_must_be_documented.reference b/tests/queries/0_stateless/02415_all_new_functions_must_be_documented.reference
index b97394742ea..89ae668331e 100644
--- a/tests/queries/0_stateless/02415_all_new_functions_must_be_documented.reference
+++ b/tests/queries/0_stateless/02415_all_new_functions_must_be_documented.reference
@@ -364,6 +364,7 @@ in
 inIgnoreSet
 indexHint
 indexOf
+indexOfAssumeSorted
 initcap
 initcapUTF8
 initialQueryID