For classic team sites, the menu to change the team site logo should be located in Site Settings > Title, Description, and logo.
If the site is created as part of an Office 365 Group, it is a modern team site. It is not feasible to change the logo of the site in this scenario. The team site's picture will follow the group's picture. To change your group's picture, you can navigate to your group's Conversation tab and click the group's picture to replace it.