To add a custom text to the top of the Blog Page Squarespace, you can follow these.
#1. First, edit Blog Page > You will see an “Add a section” option
#2. Click Add a blank section
#3. Click Add Block
#4. Choose Text
#5. Then you can enter your desired text
#6. To reduce Text section height, you can click Edit Section
and Disable Fill screen option + Reduce number in Row Count
