Back in more archaic times, your credit card would only work within a given country. Some would be limited to a single city. But modern conveniences being what they are, today there are few practical reasons why a credit card would be landlocked. So unless landlocking cards is required by some specific regulation in your country, you should be able to use it abroad.
That said, limiting where a credit card can be used does help curb the incidence of credit card theft and fraud. Because of that, some banks require that you inform them when you travel to another country so that they can unlock your card for that specific country. But unless your country has weird regulations, or you have a card from a very small provider, this process should only take a few minutes.
To answer your original question, not all credit cards can be used abroad, but most of them can. If you’d like to save money while abroad, however, getting a card made for travelers is a wise idea. Via Travelers’ guide on cheap destinations may also be useful.