1. Select icons that you’re interested in or upload an SVG;
   
2. Write down the icons codes, we’ll need them later;
3. Set a font name and hit the download button.

iOS

<key>UIAppFonts</key>
<array>
    <string>customfont.ttf</string>
</array>

Xamarin Forms Project

At this point, we have everything ready to use the icons in the app. Let’s add a new item to the ResourceDictionary in the App.xaml to handle platform specific differences:

<OnPlatform x:Key="CustomFont" x:TypeArguments="x:String">
    <On Platform="Android" Value="customfont.ttf#fontello" />
    <On Platform="iOS" Value="customfont" />
</OnPlatform>

And finally the icons. Add a label to a page, set the FontFamily and the Text properties:

<Label Text="&xe803;" x:Name="Heart" FontFamily="{StaticResource CustomFont}" FontSize="30" TextColor="White"/>

Notice that we’re using the codes that we wrote down from the Fontello service here. To make the XAML code a bit cleaner we can move all properties to a style and set only the icon code (Text property) in the label. Or even create separate styles for all frequently used icons:

<Style x:Key="Icons" TargetType="Label">
    <Setter Property="FontFamily" Value="{StaticResource CustomFont}" />
    <Setter Property="FontSize" Value="30" />
    <Setter Property="TextColor" Value="White" />
    <Setter Property="WidthRequest" Value="40" />
</Style>
<Style x:Key="LikeIcon" BasedOn="{StaticResource Icons}" TargetType="Label">
    <Setter Property="Text" Value="&#xe801 ;"/>
</Style>
<Label Text="" Style="{StaticResource Icons}" />
<Label Style="{StaticResource LikeIcon}" />