A pretty server description: two lines, colors, symbols. Copy the ready string for server.properties.
The MOTD is the server description players see in their server list. It is set in server.properties with a motd= line and can contain colours and symbols.
A classic MOTD is two lines joined by \n. Colours are written with § codes, and from 1.16 hexadecimal shades are available.
The tool assembles the finished line and shows you exactly how it will look in the server list.
Type the first and second line. Colours go in via the buttons or codes like &c, &l.
Enable the second line if you need it — it is joined in the output with \n.
Copy the value for server.properties, or the variant with real § characters.
Paste the result into server.properties and restart the server.
Usually two. Longer text either gets cut or looks unreadable in the list, so two short lines is the practical maximum.
The § character must be stored in UTF-8. If server.properties is saved in another encoding the game won't recognise it.
Yes, from 1.16 you use the §x§R§R§G§G§B§B sequence. The tool encodes it for you.