Yes, if you can come up with any of the following:
- deterministic finite automaton (DFA),
- nondeterministic finite automaton (NFA),
- regular expression (regexp of formal languages) or
- regular grammar
for some language $L$, then $L$ is regular. There are more equivalent models, but the above are the most common.
Just to complete the list: $L$ will be also regular if
- it is finite,
- you can construct it by performing certain operations on regular languages, and those operations are closed for regular languages, such as
- intersection,
- complement,
- homomorphism,
- reversal
and more, or
- using Myhill–Nerode theorem if the number of equivalence classes for $L$ is finite.
