docs: Fix PDF Classification template

docs/source/templates/pdf_classification.md

@@ -28,6 +28,10 @@ If you want to perform PDF classification, use this template. This template prom
     </Choices>
     <HyperText name="pdf" value="$pdf" inline="true"/>
 </View>
+
+<!-- {
+    "pdf": "<embed src='https://app.heartex.ai/static/samples/sample.pdf' width='100%' height='600px'/>"
+} -->
 ```
 
 ## About the labeling configuration
@@ -59,7 +63,13 @@ Use the [HyperText](/tags/hypertext.html) tag to render an inline version of the
 
 ### Input data
 
-Label Studio does not support labeling PDF-formatted files directly. Instead, convert your PDF to HTML or an image file. See [importing tasks](/guide/tasks.html) for more.  
+Label Studio does not support labeling PDF-formatted files directly. You should use the <embed> tag inside of your data for pdf loading:
+
+```
+{
+    "pdf": "<embed src='https://app.heartex.ai/static/samples/sample.pdf' width='100%' height='600px'/>"
+}
+```
 
 ## Related tags
 - [Rating](/tags/rating.html)