To customize the Gantt Chart view, you can change:

Layout options - options for drawing the links between tasks, date format, bar height, etc.
 
Bar styles - the styles for drawing the bars and displaying information about bars in the particular view

Text styles - the font styles for the various texts in the view

Bar formatting - the specific formatting of a particular bar in the chart, in case the project manager intentionally changed the format to make the task stand-out from the others by its visual presentation

Row, Column, and Cell Font formatting - the specific font formatting of a particular row, column, or cell in the sheet portion of the view, in case the project manager intentionally applied a different format to highlight the particular task, field, or value
 
Progress Lines formatting - the progress lines activated for the view and formatting options related to them

Timescale formatting - the formatting of the different timescale tiers, as well as the calendar and presentation of the working and non-working days

Gridlines formatting    - the formatting of the different gridlines for the sheet and chart portions of the view

Drawings - the different drawings and text boxes placed on the chart by the project manager, in order to place additional information for the tasks or emphasize a certain phase in the plan.

You are also able to customize the Gantt Chart views, using one of the following opportunities:

Change the different Layout options for the active Gantt Chart view.

Display, hide, or change the appearance of the timescale tiers.

Display, hide, or change the appearance of nonworking time.

Create a combination view for the Gantt Chart view to display additional information about the tasks or about the resources assigned to those tasks in a different view.