correct sentence

They are both correct. Yoong Liat, I despair of you! Where is the CONTEXT?

Both these sentences could mean the same or different things.

(a) They come to work earlier than their start time every morning. They are meant to start work at (say) 9 AM but they come at 8:45 every morning.

(b) Their start time is unusually early in the morning (when most other people are still in bed)

1. They come early to work every morning.

"early" modifies "come" (adverb telling when)



2. They come to work early every morning.

"early" modifies morning - (adjective telling what kind of morning)


There's also:

They come to work every morning early.