Change color saturation?

Colour changes are done in the Style section of the Format Inspector.

Choose the text in which you want to make the change, click the Format brush in the right end of the Tool bar, then click Style.

Then locate the Textstyle control button. Clicking the character to the right of "Textstyle" opens a menu of four choices, non of which fills your need. But further to the right is a two section icon displaying a color well and a color wheel.

Clicking the well will offer a choice of 24 pre-set colour choices.

Clicking the wheel opens a secondary window with several more colour changing tools. The first two buttons are likely the best for solving your issue.

Clicking the colour wheel (and leaving the cross hair symbol in the middle of the wheel) shows a dark black. Moving the slide in the slider control below the wheel changes the brightness of the colours in the wheel,while the pixel at the default position (centre of the wheel) moves along a grey scale ranging from black to white.

Useful, but in most cases opening too many possibilities to keep track of.

The second button—a group of sliders—opens to a menu button that when clicked offers a choice of four sliders, shown in the image below:

The last, Hue, Saturation, Brightness looks to be the most useful for what you want.

To use it, Select the text, open the Format Inspector, click the color wheel control beside Text Color, then the wheel in the inspector panel that opens, make your choice of tool, and set it to produce the saturation you want.

The empty boxes at the bottom of the Color Format Inspector are empty colour wells, into which you can paste colours you will use often.

Regards,

Barry