diff --git a/README.md b/README.md
index 7b94c9a..232ab2c 100644
--- a/README.md
+++ b/README.md
@@ -92,12 +92,37 @@ Represents a page in the document:
 
 This node represent a paragraph, a heading or any text within the document.
 
-- `category`: The type `"doc"`.
+- `category`: The classification of the text within the document.
 - `content`: A string representing the textual content.
 - `marks`: List of [marks](#marks) applied to the text, such as bold, italic, etc.
 - `attributes`: Can contain metadata like the bounding box representing where this portion of text is located in the page.
 
-
+### Category 
+Below are the various categories of text that may be found within a document:
+
+**Category Type**
+- `page-header`: Represents the header of the page.
+- `footer`: Represents the footer of the page.
+- `heading`: Any heading within the document.
+- `figure`: Represents a figure or an image.
+- `other`: Any other unclassified text.
+- `appendix`: Text within an appendix.
+- `keywords`: List of keywords.
+- `acknowledgments`: Section acknowledging contributors.
+- `caption`: Caption associated with a figure or table.
+- `toc`: Table of contents.
+- `abstract`: The abstract of the document.
+- `footnote`: Text at the bottom of the page providing additional information.
+- `body`: Main body text of the document.
+- `itemize-item`: Item in a list or bullet point.
+- `title`: The title of the document.
+- `reference`: References or citations within the document.
+- `affiliation`: Author's institutional affiliation.
+- `general-terms`: General terms section.
+- `formula`: Mathematical formula or equation.
+- `categories`: Categories or topics listed in the document.
+- `table`: Represents a table.
+- `authors`: List of authors.
 
 ### Marks
 
@@ -119,8 +144,9 @@ Attributes are optional fields that can store additional information for each no
 
 - `DocumentAttributes`: General attributes for the document (currently reserved for the future).
 - `PageAttributes`: Specific page related attributes, such as the page number.
-- `TextAttributes`: Text related attributes, such as bounding boxes.
+- `TextAttributes`: Text related attributes, such as bounding boxes or level.
 - `BoundingBox`: A box that specifies the position of a text in the page.
+- `Level`: The specific level of the text within a document, for example, for headings.
 
 
 ## Getting started
diff --git a/parse_document_model/attributes.py b/parse_document_model/attributes.py
index 79244b7..b04128d 100644
--- a/parse_document_model/attributes.py
+++ b/parse_document_model/attributes.py
@@ -1,6 +1,7 @@
 from abc import ABC
+from typing import Optional
 
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 
 class BoundingBox(BaseModel):
@@ -25,3 +26,4 @@ class PageAttributes(Attributes):
 
 class TextAttributes(Attributes):
     bounding_box: list[BoundingBox] = []
+    level: Optional[int] = Field(None, ge=1, le=4)
diff --git a/test/test_validation.py b/test/test_validation.py
index 339764f..e564f9d 100644
--- a/test/test_validation.py
+++ b/test/test_validation.py
@@ -66,3 +66,36 @@ def test_url_marks():
         else:
             with pytest.raises(ValueError):
                 UrlMark(**mark_json)
+
+
+def test_text_attributes_level():
+    valid_text_attributes = [
+        {"bounding_box": [], "level": 1},
+        {"bounding_box": [], "level": 2},
+        {"bounding_box": [], "level": 3},
+        {"bounding_box": [], "level": 4},
+        {"bounding_box": [], "level": None},
+        {"bounding_box": []},
+        {}
+    ]
+
+    for attributes_json in valid_text_attributes:
+        text_attributes = TextAttributes(**attributes_json)
+        assert isinstance(text_attributes, TextAttributes)
+        assert isinstance(text_attributes.level, (int, type(None)))
+        if text_attributes.level is not None:
+            assert text_attributes.level in range(1, 5)
+            assert attributes_json["level"] == text_attributes.level
+        else:
+            assert "level" not in attributes_json or attributes_json["level"] is None
+
+    invalid_text_attributes = [
+        {"bounding_box": [], "level": -1},
+        {"bounding_box": [], "level": "invalid"},
+        {"bounding_box": [], "level": 2.5},
+        {"bounding_box": [], "level": 5},
+    ]
+
+    for attributes_json in invalid_text_attributes:
+        with pytest.raises(ValueError):
+            TextAttributes(**attributes_json)