The translations for the linguistic term "WORD FORMS" in Google Translate and PONS.EU into Spanish are more or less the same "Formas de Palabras", but this translation doesn't seem to have the same sense that it has in English (See here for an explanation and definition of this term).
1Word-form is one of the three meanings of "word" in English; it may or may not have such a fixed technical status in Spanish, where one can identify and speak of radical, terminación, desinencia, and tema for almost every word.– jlawlerJul 2, 2013 at 17:35
In linguistics we normally call lema the headword of a word (that is, the way we would find it in a dictionary: its form in singular/masculine/infinitive). All the inflections of a lemma (plurals, conjugated verbs, etc) are called formas.
So dog would be a lema, and its formas (word forms) would be dog and dogs.
Probably the easiest way to answer a question like this, is simply to read the Spanish version of the wiki page you linked in your question. Based on that, I believe the answer you seek is: