If you run a Minecraft server yourself, you can customise the MOTD with color codes and format codes.
Now, you can customize your text styling and color as per your desire.
If you didn't know where to find the § symbol then don't worry I will guide you that as well.
You can find the on this page.
Finally, if neither of the above-mentioned options works for your device, you can simply copy the symbol online and paste it to Minecraft.
To solve it, you can modify the text color.