Here are some examples:
Wife - wives
knife - knives
thief - thieves
life - lives
scarf - scarves
leaf - leaves
loaf - loaves
half - halves
calf - calves
wolf - wolves
shelf - shelves
hoof - hooves
self - selves
The plural of loaf is loaves. Some, but not all words ending in F change it to a V and add -es to form the plural (thief-thieves, hoof-hooves).
The spelling rule of changing a final "f" to "v" and adding "es" when making a noun plural helps ensure proper pronunciation. When you add an "s" to words that end in "f," often the pronunciation becomes awkward, so changing it to "v" helps maintain the sound of the word.
usually you chAnge it to a "v" like leaf to leaves
Words like half (halves), wife (wives), dwarf (dwarves), hoof (hooves).
The rule for forming the plural of the noun 'elf' is to change the ending 'f' to a 'v' and add 'es'. The plural noun is elves.