Write a program to print the sum of 1 to n. While calculating sum omits the numbers which are multiples of x. Note :use the concept of continue.

To add to what Patrice has - rightly - said: indentation in Python is significant.
All code indented to the same level forms a single code block whioch only ends when a lesser level on indentation is found,
So this code:

For i in range(0,n+1):
    if(i%6==0):
        Continue 
        Sum=sum+i
        print(int(sum))
print(sum)

Contains two code blocks inside the for loop, one nested inside the other. One code block is the if statement:

For i in range(0,n+1):
    if(i%6==0):
       ...
print(sum)

The other is the content of the if which is only executed if the condition is true, and is executed in its entirety:

Continue
Sum=sum+i
print(int(sum))

Since the first instruction in that code block causes the for loop to immediately carry on with the next iteration ignoring all further code in the loop body, you get no sensible output.

As Partrice says: indent your code to multiple blocks:

For i in range(0,n+1):
    if(i%6==0):
        Continue 
    Sum=sum+i
    print(int(sum))
print(sum)

And it'll do what you want.

Alternatively, reverse the test:

For i in range(0,n+1):
    if(i%6 != 0):
        Sum=sum+i
        print(int(sum))
print(sum)

And you don't need the continue at all - which is more readable!

for i in range (0,n+1);
if (i%6==0);
continue
sum=sum+i
printf (int(sum))
printf (sum)