docs: Supplement English intro

src/form/README.md

@@ -1,5 +1,9 @@
 # Form
 
+### Intro
+
+It is used for data entry and verification, and supports input boxes, radio buttons, check boxes, file uploads and other types.
+
 ### Install
 
 Register component globally via `app.use`, refer to [Component Registration](#/en-US/advanced-usage#zu-jian-zhu-ce) for more registration ways。