Refer to modelcard creator app from doc (#1184)

* Refer to modelcard creator app from doc

* rephrase

Author: Wauplin

docs/source/how-to-model-cards.mdx

@@ -4,6 +4,12 @@ The `huggingface_hub` library provides a Python interface to create, share, and
 Visit [the dedicated documentation page](https://huggingface.co/docs/hub/models-cards)
 for a deeper view of what Model Cards on the Hub are, and how they work under the hood.
 
+<Tip>
+
+[New (beta)! Try our experimental Model Card Creator App](https://huggingface.co/spaces/huggingface/Model_Cards_Writing_Tool)
+
+</Tip>
+
 ## Loading a Model Card from the Hub
 
 To load an existing card from the Hub, you can use the [`ModelCard.load`] function. Here, we'll load the card from [`nateraw/vit-base-beans`](https://huggingface.co/nateraw/vit-base-beans).