Prepositions are words used to express the relationship of a noun and pronoun in a sentence. “Upon” and “On” are both prepositions. In most cases, they are used interchangeably. Upon is more formal than on.
Upon his many usages and meanings.
It refers to someone or something in an elevated position, in contact with, approximately or completely, and on the occasion of.
Examples of this word in a sentence
1. The boy mounted upon his horse and was gland.
2. Christmas is upon us, and I need to buy gifts for the whole family
On the other hand, “on” has a lot of different meanings and usage. It is used to show the position above, which is in contact with or supported by, it also shows location or proximity, to express a process, etc.
Examples of the sentence using “on” include:
1. A pimple on his face.
2. He rode on a train.
3. He went on and on.