Let's take a look at the difference between the two main types of adjectives: い-adjectives and な-adjectives.
い-adjectives always end with the hiragana い, like 高たかい (high/tall) or 安やすい (cheap). These words work on their own and can be directly conjugated.
For example:
な-adjectives don't end in い, and need な when placed before a noun. For instance, 綺麗きれい (pretty) → 綺麗 な 人ひと (a pretty person)
They follow a different pattern when conjugated in sentences.