You might need to know if you’re working on a Team Site or a Publishing site, or some other kind of SharePoint Site. To check, do a “View Page Source” on any page in the site and search on “g_wsaSiteTemplateId”
See the following post to find out what that template ID is https://www.technologytobusiness.com/microsoft-sharepoint/sharepoint-online-site-template-id
Learning SharePoint 