IApplication.Caption Property

The caption of this application.

[Visual Basic 6.0]
Property Caption As String

[Visual Basic .NET]
Public Property Caption As String

[C#]
public string Caption {get; set;}

Available with ArcGIS Desktop.

The Caption is the string that appears as the title of the application's main window.

[C#]

The following function sets the title of the main desktop application window.

public void SetCaption(IApplication app)
{
   app.Caption = "My Custom Application";
}

[Visual Basic 6.0]

This VBA macro sets the title of the main desktop application window.

 Public Sub SetCaption()
   Application.Caption = "My Custom Application"
 End Sub

[Visual Basic .NET]

The following Sub sets the title of the main desktop application window.

 Public Sub SetCaption(app As IApplication)
   app.Caption = "My Custom Application"
 End Sub

EDN: ESRI Developer Network