Hello, Claire,
The HTML-like text formatting mechanism uses a few plain HTML tags to display formatted text such as font style, font color, font size, etc. The previously referred help article lists the supported tags: https://docs.telerik.com/devtools/winforms/telerik-presentation-framework/html-like-text-formatting
The relative position is not supported by the HTML-like functionality in the Telerik UI for WinForms suite.
If you want to shift the group text, you can handle the ViewCellFormatting event and either set the CellElement.TextAlignment property to the desired value or set the CellElement.Padding specifying the fixed left padding:
private void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
if (e.Row is GridViewGroupRowInfo)
{
e.CellElement.DisableHTMLRendering = true;
e.CellElement.Padding = new Padding(200, 0, 0, 0);
}
else
{
e.CellElement.DisableHTMLRendering = false;
e.CellElement.ResetValue(LightVisualElement.PaddingProperty, ValueResetFlags.Local);
}
}

Should you have further questions please let me know.
Regards,
Dess | Tech Support Engineer, Sr.
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