To make Text Bigger in Squarespace, you can use Scale option or CSS code.
#1. Highlight text
#2. Click Scale icon
#3. Result
#4. In case you want to change a specific word text bigger only. You can highlight text then press Ctrl U
we will have
Then use this code to Custom CSS box
div#block-d9fbcf76b56f4983068b p span[style="text-decoration:underline"] {
text-decoration: none !important;
font-size: 30px !important;
}
result