Type conversion, also known as typecasting, is the process of changing the data type of a variable from one type to another in Python. Python is a dynamically-typed language, which means that the data type of a variable is determined at runtime based on the value assigned to it. However, sometimes it may be necessary to change the data type of a variable to perform certain operations or to avoid type errors.

In Python, type conversion can be achieved using built-in functions such as int(), float(), str(), bool(), and others. These functions take an argument of one data type and return an equivalent value of the desired data type.

For example, to convert a string to an integer, we can use the int() function as follows: 

x = "123"
y = int(x)
print(y) # output: 123

Likewise, to convert an integer to a string, we can use the str() function as follows: 

x = 123
y = str(x)
print(y) # output: "123"

Type conversion is important in Python to ensure that the program runs without any errors and produces the expected output. However, it is important to use type conversion carefully and to be aware of any potential side effects or loss of precision that may occur during the conversion process.