Flask is a light-weighted or micro-framework written in Python is used for web development applications. For suppose, if someone asks you to travel 10 km and choose a mode of transport to travel, then what would you select:
Definitely, you would choose either a car or motorbike because in Python web development, Walk is like not using any framework, Bike is like using Flask, and Car is like using Django.
Therefore, it is not necessary to choose Flask or Django Frameworks for your application but these frameworks make your life less miserable.
Also, watch this video to create a simple application in Python Flask: