Adjust the Gantt Chart Timeline
The Gantt chart has 4 timeline zoom levels: quarter, month, week and day. Anyone with access to the sheet can quickly change the timeline zoom level by clicking the Zoom In or Zoom Out icons in the Gantt Chart header:
While anyone can use the Zoom in/out icons to adjust their own view, changes made by Viewers and Editors won't affect other collaborators or be displayed in an export. Only the sheet owner and collaborators with Admin access can make changes to the exported timeline.
NOTE: In the Gantt chart of a Report, all collaborators except Viewers are able to save changes to the Gantt chart timeline, and these changes will be reflected in an export.
The sheet owner and shared collaborators with Admin access can further configure and customize the Gantt chart's Primary and Secondary Headers by modifying the Timeline Display found in the sheet's Project Settings.