As tab system in wpf there is the TabControl, where inside there can be n TabItem, which are the tabs themselves.
Ex:
<Window x:Class="WpfApp1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid>
<TabControl>
<TabItem Header="Aba 1">
</TabItem>
<TabItem Header="Aba 2">
</TabItem>
</TabControl>
</Grid>