All objects share class or static variables. An instance or non-static variables are different for different objects (every object has a copy). For example, let a Computer Science Student be represented by class CSStudent. The class may have a static variable whose value is “cse” for all objects. And class may also have non-static members like name and roll. In C++ and Java, we can use static keywords to make a variable a class variable. The variables which don’t have a preceding static keyword are instance variables. See this for Java example and this for C++ example.
The Python approach is simple; it doesn’t require a static keyword.

All variables which are assigned a value in the class declaration are class variables. And variables that are assigned values inside methods are instance variables.

# Python program to show that the variables with a value
# assigned in class declaration, are class variables

# Class for Computer Science Student
class CSStudent:
stream = 'cse' # Class Variable
def __init__(self,name,roll):
self.name = name # Instance Variable
self.roll = roll # Instance Variable

# Objects of CSStudent class
a = CSStudent('prutor', 1)
b = CSStudent('Nerd', 2)

print(a.stream) # prints "cse"
print(b.stream) # prints "cse"
print(a.name) # prints "prutor"
print(b.name) # prints "Nerd"
print(a.roll) # prints "1"
print(b.roll) # prints "2"

# Class variables can be accessed using class
# name also
print(CSStudent.stream) # prints "cse"

# Now if we change the stream for just a it won't be changed for b
a.stream = 'ece'
print(a.stream) # prints 'ece'
print(b.stream) # prints 'cse'

# To change the stream for all instances of the class we can change it
# directly from the class
CSStudent.stream = 'mech'

print(a.stream) # prints 'mech'
print(b.stream) # prints 'mech'
Output:

cse
cse
prutor
Nerd
1
2
cse
ece
cse
ece
mech