DAX functions are similar to Excel functions, but they are specifically designed for working with data models and have a different syntax. DAX functions are also designed to work with large datasets and are optimized for performance.
There are many different types of DAX functions, some of which includes -
Aggregation functions
Date and time functions
Filter functions
Information functions
Text functions
Statistical functions
If you are interested in learning more about DAX then for your reference I am attaching a video tutorial by experts from Intellipaat.