Both forms are correct.
Travelling is the correct British English form, however traveling is also used; it is widely accepted in American English. This is because of Noah Webster’s dictionary of 1828, in which the author simplified many British spellings and standardized them as American English correct forms. Therefore both travelling and traveling are correct, but they are used in different parts of the English-speaking world.

Correct spelling, explanation: preferred in American English.

Correct spelling, explanation: preferred in British English.

Definition of travelling/traveling:
verb, gerund form of travel, to move from one place to another, to have a trip or journey
Travelling by car is much more expensive than travelling by coach, but is faster and more comfortable.
I have traveling. I prefer to stay at home and relax in front of the tv.