The number one difference between to and too is that the word ‘to’ can function as a preposition, marker, and adverb, whereas the word ‘too’ can only function as an adverb. For an easy understanding of the two words, I will explain how the two are used in the English language. As a marker, the word ‘to’ is used to mark verbs. For example, I need to go. As a preposition, you can use it to indicate the destination. For example, we are going to the police station. Also, as a preposition, you can use it to indicate the result of an action. For example, he has been lifted to the position of the general manager. As an adverb, it means towards a touching or engaging position. On the other hand, the word ‘too’ can be used as an adverb to mean likewise, in addition, to a high degree, and can be used to contradict a statement. For example, the idea is too good to be discarded.