السلام عليكم
"...The scholars (may Allah have mercy on them) stated that what is prescribed is for the worshipper to recite quietly in
naafil prayers offered during the day, and when praying at night, he has the choice between reciting out loud or quietly, but reciting out loud is better....
With regard to the
naafil prayer of
Maghrib, the third
rak‘ah or
Witr,
qiyaam al-layl and the
Sunnah of Fajr, the worshipper has the choice between reciting out loud or quietly, although reciting out loud is better, unless reciting quietly helps him to focus more, or he has people with him who will be disturbed by his reciting out loud, such as one who sleeping or one who is sick, and the like...."
https://islamqa.info/en/answers/6761...ers-and-rakahs