Can I put my tours in folders or group them by client?

Not in folders: My Tours is one list. To find a tour in a long list, type a few letters of its name or category in the search box at the top right, choose a chip such as Hosted, Published, Drafts or Shared, and sort by Sort: last edited, Sort: most views or Sort: name.

A client's name at the start of each tour's name, or the tour's category, lets the search box gather a client's tours together. Panorama groups are a different thing: they sort the rooms inside one tour into floors or areas (Organize scenes into panorama groups).