There are two types of logos you can add in GoHire, internal logos and external logos.
Internal logos are used for use within GoHire and you can add an internal logo in Settings > Company Settings. The recommendation for the internal logos is square 1:1 ratio.
External logos are used for your Career Pages and Job Pages. You can add an external logo in your Careers Page Designer. The recommendation for the external logo is a rectangle 5:2 ratio.