diff --git a/doc/source/whatsnew/v2.0.0.rst b/doc/source/whatsnew/v2.0.0.rst
index 22f6659367683..a01c31cd614b0 100644
--- a/doc/source/whatsnew/v2.0.0.rst
+++ b/doc/source/whatsnew/v2.0.0.rst
@@ -77,6 +77,47 @@ be set to ``"pyarrow"`` to return pyarrow-backed, nullable :class:`ArrowDtype` (
         df_pyarrow = pd.read_csv(data, use_nullable_dtypes=True, engine="pyarrow")
     df_pyarrow.dtypes
 
+Copy on write improvements
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A new lazy copy mechanism that defers the copy until the object in question is modified
+was added to the following methods:
+
+- :meth:`DataFrame.reset_index` / :meth:`Series.reset_index`
+- :meth:`DataFrame.set_index` / :meth:`Series.set_index`
+- :meth:`DataFrame.set_axis` / :meth:`Series.set_axis`
+- :meth:`DataFrame.rename_axis` / :meth:`Series.rename_axis`
+- :meth:`DataFrame.rename_columns`
+- :meth:`DataFrame.reindex` / :meth:`Series.reindex`
+- :meth:`DataFrame.reindex_like` / :meth:`Series.reindex_like`
+- :meth:`DataFrame.assign`
+- :meth:`DataFrame.drop`
+- :meth:`DataFrame.dropna` / :meth:`Series.dropna`
+- :meth:`DataFrame.select_dtypes`
+- :meth:`DataFrame.align` / :meth:`Series.align`
+- :meth:`Series.to_frame`
+- :meth:`DataFrame.rename` / :meth:`Series.rename`
+- :meth:`DataFrame.add_prefix` / :meth:`Series.add_prefix`
+- :meth:`DataFrame.add_suffix` / :meth:`Series.add_suffix`
+- :meth:`DataFrame.drop_duplicates` / :meth:`Series.drop_duplicates`
+- :meth:`DataFrame.reorder_levels` / :meth:`Series.reorder_levels`
+
+These methods return views when copy on write is enabled, which provides a significant
+performance improvement compared to the regular execution (:issue:`49473`). Copy on write
+can be enabled through
+
+.. code-block:: python
+
+    pd.set_option("mode.copy_on_write", True)
+    pd.options.mode.copy_on_write = True
+
+Alternatively, copy on write can be enabled locally through:
+
+.. code-block:: python
+
+    with pd.option_context("mode.copy_on_write", True):
+        ...
+
 .. _whatsnew_200.enhancements.other:
 
 Other enhancements