Looking at your current level, I gather this is an old question of yours. So then, for any new users, here is an answer:
You only need to use an apostrophe for the feminine words following una, or alla, della, dalla, and so on, and for masculine nouns where the initial letter A is involved.
un orso would only use the apostrophe if it were "una orsa"-- becoming un'orsa -- and orsa isn't a bear, orso is.
- una anatra becomes un'anatra
- un anno becomes un'anno
- al albergo becomes all'albergo
- nella acqua becomes nell'acqua