How do i create a text box as part of the template

Hello,
I recently started a site https://www.casualdressshoesnews.com and am doing pretty well.

However, I would like to create a box under the header that is on the top of every single page of the site.

An example would be the “online security guard training and career center” section on https://www.securityguardtraininghq.com . It has a small text box with a picture that appears underneath the header on every single page.
How would I create something like that?

Thanks in advance!