What is the use of datatypes

Answer 1

In computer science and computer programming, a data type or simply type is an attribute of data which tells the compiler or interpreter how the programmer intends touse the data. Most programming languages support common data types of real, integer and boolean.
Source: https://en.m.wikipedia.org/wiki/Data_type

Answer 2

The data type of a value (or variable in some contexts) is an attribute that tells what kind of data that value can have.