In Python, you can delare a variable simply so

my_var = "hello"

You can also declare multiple variables at once

a, b, c = "a", "b", "c"

As for types, Python is a dynamically typed language. This means that you don't have to declare the type and the type of a variable can be change throughout its lifetime.

my_var = 3

To infer the type of a variable, you can use the type() function. For example:

print(type("string variable"))

print(type(350))

print(type(True))

While Python does not have constants, that is variables that do not change, it is customary to declare them while in all caps

MY_CONSTANT = "should not change"