The noun-(이에/예)요 form is used like the English word 'is'. It means something is the noun. When the noun ends in a vowel 예요 is added. When it ends with a consonant 이예요 is added. For example:
의자예요. (It) is a chair. 책이에요. (It) is a book.
As Korean uses a subject-object-verb word order, and the subject may often be omitted when it is implied by the context, these examples are actually complete sentences.