In real life, Humans need resources like food, water, and many essential items every day to survive, similar to humans, an android application also needs some resources. When you open any android application, you will see texts, fonts, colors, styles, and many basic views. Since these things are common in many android applications, we consider them as resources that you need to set up when you start developing the android app.
Resources are a collection of static files and basic configuration of layouts, fonts, color, styles, dependencies, and many more that are being used throughout the app. Therefore I would highly recommend you learn about all kinds of resources that an android app needs.
According to Android documentation, there are 11 types of resources such as animator, anim, color, drawable, mipmap, layout, menu, raw, values, XML, and font that are commonly used.