option key (or the Alt key on a standard keyboard) while you press the Enter/Return
that will add the blank 🌈 line to separate the text in a single texT message. Add Line
iMessage on Mac - PosiTek positek : 🌈 add-line-
new line/paragraph - Alvin Alexander
inalexander : misc macos-messages-app-how-add-neW-line-parag...