A Z-seam in preview mode.

[nesergen 0]

Dealing with the Z seam settings. And I want to see how changes in the settings affect the printed model. Therefore, I go to the preview mode, but I do not see where the seam is located. Can I see the location of the seam in preview mode?

[Smithy 1,141]

Turn on coasting, then you see it much better. But don't forget to turn it off again before printing, if you don't want to use it.

[GregValiant 1,110]

And under "Color Scheme" "Line Type" if you turn on Travels you should notice the seam.  If you turn off Helpers, Shell, and Infill the seam and (if it's different) the layer start point should be fairly easy to pick out.

[nesergen 0]

it would be nice to render the seam on a 3d model. And highlight it with color.

[Smithy 1,141]

Yes would be a nice feature, both methods are not optimal.

But you can create feature request here if you want: https://github.com/Ultimaker/Cura/issues

[Dim3nsioneer 557]

Such requests already exist. E.g. https://github.com/Ultimaker/Cura/issues/6072