花朵 means "flower" and specifically emphasizes the blossom or bloom of a plant. While 花 is the more common everyday word, 花朵 is slightly more descriptive and is often used in literary or vivid descriptions.
春天一到,树上开满了粉色的花朵。
chūntiān yí dào, shù shàng kāimǎn le fěnsè de huāduǒ.
As soon as spring arrives, the trees are covered with pink blossoms.
她捡起一朵掉在地上的花朵闻了闻。
tā jiǎnqǐ yì duǒ diào zài dìshang de huāduǒ wén le wén.
She picked up a flower that had fallen on the ground and smelled it.
那些花朵在阳光下显得格外鲜艳。
nàxiē huāduǒ zài yángguāng xià xiǎnde géwài xiānyàn.
Those flowers looked especially vibrant in the sunlight.