Tested in TM², details may vary in other versions of Trackmania.
To format your text, you can use the following modifiers:
[$w] All following text will be wide.
Reset by using Reset Width or Reset All Styles.
$w Example [$n] All following text will be narrow.
Reset by using Reset Width or Reset All Styles.
$n Example [$m]Resets following text to default width.
$w Example1 $m Example2 [$i] All following text will be italic.
Reset by using another Italic tag, or Reset All Styles.
$i Example1 $i Example2 [$t] All following text will be in uppercase letters.
Reset by using another Uppercase tag, or Reset All Styles.
$t Example1 $t Example2 [$o] All following text will be bolded.
Reset by using another Bold tag, or Reset All Styles.
$o Example1 $o Example2 [$s] All following text will have a shadow.
Reset by using another Shadow tag or Reset All Styles.
$s Example1 $s Example2 [$hex] All following text will have the specified color.
Colors use 3-digit hexadecimal code (0123456789ABCDEF), e.g. $fff for white.
Reset by using Reset Color or Reset All Styles.
Note: The game will also recognize 1 and 2 digit hex codes, i.e. $f for red or $0f for green.
$0d0 Example1 $9 Example2 [$g]Resets following text to default color.
$0d0 Example1 $g Example2 [$z]Resets everything to default.
$o$w$i$ff0 Example1 $z Example2 [$$] Allows you to type a $ without it being interpreted as a formatting tag.
$$ The game also recognizes the following modifiers for links, but they are not supported by this tool for the sake of simplicity.
[$l[URL]text] Link to an external site.
The [URL] part is optional, so e.g. $lhttps://example.com will also work.
[$h]Link to a manialink address.
[$p]Link to a player script returning a manialink.
Credit to Trackmania Wiki for the FA icons list.