I suppose you are looking at a Gantt Chart representation of your schedule. I noticed there is a Online Gantt Chart software called https://www.teamgantt.com/. Are you referring to this? If yes, I don’t see it requires Microsoft Project to be installed. Meanwhile, you can use the powerful scheduling capabilities of Microsoft Project to create schedules in desktop (https://www.microsoft.com/en-us/p/project-professional-2019/cfq7ttc0k7cj?activetab=pivot%3aoverviewtab) and online (which requires a project online license)