WordPress Span around tm symbol in theme title

I’m new to wordpress so apologies if this is a simple issue.

I want to add a span around a part of my theme title that I then adjust via css.

Specifically, I want the title to be ="MyWord™” where the ™ makes a trademark symbol.

I want to make the trademark symbol smaller so I want to put a span around it with an id “tm_logo” so that I can set a smaller font (i’m assuming via css).

I think I need to add something like what’s shown below to functions.php. However would then changing the css still be enough? I’ve tried adding the following to functions.php with no luck — it’s not even pulling in the title. I’m not sure what else I need to change to make it pull from that function.

` function my_title() {
$part1 = “MyWord”;

$part2 = ‘<span id=”tm_logo”>™</span>’;

$title = $part1.$part2;

return $title;
}
`

Any help would be much appreciated!