There are many different determiners in the English language.
Articles are among the most common of the determiners. A, an, and the all express the definiteness and specificity of a noun. For example, “the” is a definite article, meaning the person using the word is referring to a specific one. On the other hand, “a” or “an” are indefinite.
Demonstratives, such as this, that, these and those, require a frame of reference in which an individual can point out the entities referred to by a speaker or a writer.
Quantifiers, such as all, few, and many, point out how much or how little of something is being indicated.
When referring to an entity that belongs to another, you can use possessives. My, your, their, and its are a few examples.