Changing the logo is easy, changing the name isn’t (and we do not plan to support changing it - “Indico” is the name of the product after all).
To change the logo, simply set LOGO_URL = '...' in indico.conf; please see the documentation for details: Settings — Indico 3.3.6 documentation
PS: If https://ghf.unige.ch/ is your instance, please note that you’re using a version that’s nearly 2 years old. You need to update!
If this is your instance, you should probably also set the PUBLIC_SUPPORT_EMAIL email address in the config file; that way you have a “contact” link in the footer, and people are less likely to fall back to googling “Indico support” (and then often ending up on the CERN or UN indico sites).