create a folder for first app

app_hello_world/main.py

@@ -0,0 +1,6 @@
+from fastapi import FastAPI
+app = FastAPI()
+# Expose an endpoint at the root of URL
+@app.get("/")
+def greet_json():
+    return{"Hello":"World!"}

app_hello_world/requirements.txt

@@ -0,0 +1,2 @@
+fastapi
+uvicorn[standard]