Is the plural of a noun plus s or es?

Is the plural of a noun plus s or es?

There are many kinds of plural forms of nouns. 1. Add s directly, such as girls, teachers, etc. 2. Add es after them, which are generally words ending with CH, x, SH, etc., such as churches, boxes, etc. 3. The singular and plural are homomorphic, that is, unchanged, such as sheet, people, etc. 4