Is this the classical iris data set used in ML?
To get help you must give the structure of your json file. Here https://www.kaggle.com/rtatman/iris-dataset-json-version there is a version of iris data set in json format, which consists in a list of dicts:
I read it as follows:
import json
with open('iris.json', 'r') as fp:
jdata = json.load( fp)
print(type(jdata)) #it is list
Let us print the first list element: print(jdata[0])