Your MOTD is the one line of marketing every player sees before joining. The pattern that works: line one says what the server is (gamemode, version, headline feature), line two gives a reason to click today — a season, an event, a wipe date. Colors help it stand out in a wall of gray server entries, but two or three per line is plenty; rainbow text reads as noise.
The vanilla server reads the MOTD from the motd= key in server.properties, where the § sign must be escaped as \u00A7 and a line break as \n — that is exactly what the "for server.properties" output gives you. Some panels and plugins (and proxies like Velocity or BungeeCord) accept raw § text or even &-codes directly; for those, use the raw output instead.
The "message of the day" shown under your server's name in the multiplayer server list. It is set by the motd= line in server.properties and supports two lines of text with color and formatting codes.
Use the code buttons above — colors become § codes and the second field becomes a \n line break. In server.properties the § character must be written as the escape sequence \u00A7; the escaped output below does that for you.
Keep each line under roughly 45 visible characters. The server list column has a fixed width, and longer lines are cut off on smaller windows.