They comes home early everyday.

The above sentence is wrong, if I want to express: You put an extra "s" on the word come, and advise the writer, is the underlined part correct. Thanks very much!
No, it is not an extra 's' because there is no other 's' in the word. You have incorrectly added an 's' onto the word 'come'.

Also, the writer has incorrectly spelt 'every day'.
almost make a mistake! Thanks a lot!!!