Hello PR,
To edit the header banner, please navigate to Dashboard > Static Blocks > edit the Header promo banner block as per your requirements. For a better reference, please see the image provided at the following link: https://postimg.cc/nj159xbk.
To add a Header banner, please navigate to Dashboard > Appearance > Widgets > Header banner > add 8theme static block widget. For a better reference, please see the image provided at the following link: https://postimg.cc/r04zChFz.
We hope this information is helpful.
Best Regards,
8Theme’s Team