docs(document_understanding.md): clarify 'format' param usage

docs/my-website/docs/completion/document_understanding.md

@@ -187,6 +187,97 @@ curl -X POST 'http://0.0.0.0:4000/chat/completions' \
 </TabItem>
 </Tabs>
 
+## Specifying format 
+
+To specify the format of the document, you can use the `format` parameter. 
+
+
+<Tabs>
+<TabItem value="sdk" label="SDK">
+
+```python
+from litellm.utils import supports_pdf_input, completion
+
+# set aws credentials
+os.environ["AWS_ACCESS_KEY_ID"] = ""
+os.environ["AWS_SECRET_ACCESS_KEY"] = ""
+os.environ["AWS_REGION_NAME"] = ""
+
+
+# pdf url
+file_url = "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf"
+
+# model
+model = "bedrock/anthropic.claude-3-5-sonnet-20240620-v1:0"
+
+file_content = [
+    {"type": "text", "text": "What's this file about?"},
+    {
+        "type": "file",
+        "file": {
+            "file_id": file_url,
+            "format": "application/pdf",
+        }
+    },
+]
+
+
+if not supports_pdf_input(model, None):
+    print("Model does not support image input")
+
+response = completion(
+    model=model,
+    messages=[{"role": "user", "content": file_content}],
+)
+assert response is not None
+```
+</TabItem>
+<TabItem value="proxy" label="PROXY">
+
+1. Setup config.yaml
+
+```yaml
+model_list:
+  - model_name: bedrock-model
+    litellm_params:
+      model: bedrock/anthropic.claude-3-5-sonnet-20240620-v1:0
+      aws_access_key_id: os.environ/AWS_ACCESS_KEY_ID
+      aws_secret_access_key: os.environ/AWS_SECRET_ACCESS_KEY
+      aws_region_name: os.environ/AWS_REGION_NAME
+```
+
+2. Start the proxy 
+
+```bash
+litellm --config /path/to/config.yaml
+```
+
+3. Test it! 
+
+```bash
+curl -X POST 'http://0.0.0.0:4000/chat/completions' \
+-H 'Content-Type: application/json' \
+-H 'Authorization: Bearer sk-1234' \
+-d '{
+    "model": "bedrock-model",
+    "messages": [
+        {"role": "user", "content": [
+            {"type": "text", "text": "What's this file about?"},
+            {
+                "type": "file",
+                "file": {
+                    "file_id": "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf",
+                    "format": "application/pdf",
+                }
+            }
+        ]},
+    ]
+}'
+```
+</TabItem>
+</Tabs>
+
+
 ## Checking if a model supports pdf input
 
 <Tabs>