Hi Katharine,
If there isn’t an option you’ll need to use CSS for this. The property you need to change is the letter-spacing CSS property. You can find some info about it online, e.g., the W3Schools website
https://www.w3schools.com/cssref/pr_text_letter-spacing.asp
If you already know how to apply CSS to your page title, you’re all set, otherwise, let me know if it’s all page titles or post titles you want to change, or send me a link to your site and I’ll be able to target the right elements and give you the exact CSS rule for this.
It’s a small change, but still it’s better made in a custom css editor or a child theme.
I hope this helps.