Under Animation, you can select a fade-in and/or fade-out for the text with which it is faded in or out. If you  click on the Tfx Adjust button next to the animation selection, you can customize the respective animation.

If an existing Text animation is modified, it appears with an asterisk after the name.

It is not only from the Properties window that you can select a Text fade-in or fade-out. In the Toolbox you can call the same Text animations as under Properties.

Drag the desired Text effect from the Toolbox onto the image.

If you want to use the same Text effect for all images, select all images by pressing the keys  Ctrl  +  A . Now double-click on the desired Text effect.
If the same Text effect is to be used for several images together, then hold down  Ctrl  and click the mouse on the images to which the Text effect is to be applied. Once the images are selected, double-click the desired Text effect in this case as well.

To remove a Text effect, first select the object in question in the Timeline. Then double-click the Remove text effect icon at the very top of the Toolbox.

In Stages you can also  control the duration of the Fade-in or Fade-out of the text via the Keyframe track. To do this, open the keyframe track and click in the track for the text animation.
Here there is a keyframe for fade in and fade out (if activated), with which you can control the end of the fade in or the beginning of the fade out.