Nehemia 8:10 records that the people in Jerusalem were told to, among other things, provide food for Rosh Hashana for those who are lacking:
ויאמר להם לכו אכלו משמנים ושתו ממתקים ושלחו מנות לאין נכון לו כי־קדוש היום לאדנינו ואל־תעצבו כי־חדות יהוה היא מעזכם
He further said to them, “Go, eat choice foods and drink sweet drinks and send portions to whoever has nothing prepared, for the day is holy to our Lord. Do not be sad, for your rejoicing in the LORD is the source of your strength.”
Is there anywhere in halachic practice or minhag that codify providing food for the poor specifically for Rosh Hashana? The idea of communal charity prior to Pesach, kimcha de'pischa, has a long history, but I am not familiar with such a practice for Rosh Hashana. (Modern Israel features many charity drives to provide food before Rosh Hashana, but I have never seen this practice anchored in halachic sources specific to Rosh Hashana).