Which one is correct or both correct?

兩句嘟唔啱卜,應該係:
He has bought some foods today.
(1) 你講啲係 ( today ) 所以要用現在完成式.
(2) ( some ) 係眾數,所以 ( s )加在名詞裡.

He bought some food today.
Because there is a word (today) so we use past tense(bought)
Using past tense:
We use the simple past tense to talk about things that happened in the past . We often use the simple past tense with time words. We can put the time words at the beginning or at the end of a sentence. Some common time words include ‘yesterday’, ‘last week’, ‘last month’ and ‘three years ago’.

he bought... because when you said this behavior (buying food), it's already done! then we should mention this action in past tense