You can update your strapline message by following these simple steps:
Click the home drop-down, then select the notices folder.
Next to Notices, click the three dots.
Click New notice, then select the information type.
Select the shape and symbol you'd like for the icon.
Add your content, then save and publish.
Click back to the home section, then scroll to notices.
In the drop-down, select your notice, then click Add.
Select Apply to Descendants, then save and publish.