Adding shadows to custom shader

I know nothing about shaders and copied a shader from the internet with a fresnel effect I liked. It seems like the shaders doesn't support receiving shadows yet. How can I change the shaders code to add shadows?

Thanks in advance!

 Shader "Custom/Fresnel" {
     //show values to edit in inspector
     Properties {
         _Color ("Tint", Color) = (0, 0, 0, 1)
         _MainTex ("Texture", 2D) = "white" {}
         _Smoothness ("Smoothness", Range(0, 1)) = 0
         _Metallic ("Metalness", Range(0, 1)) = 0
         [HDR] _Emission ("Emission", color) = (0,0,0)
 
         _FresnelColor ("Fresnel Color", Color) = (1,1,1,1)
         [PowerSlider(4)] _FresnelExponent ("Fresnel Exponent", Range(0.25, 4)) = 1
     }
     SubShader {
         //the material is completely non-transparent and is rendered at the same time as the other opaque geometry
         Tags{ "RenderType"="Transparent" "Queue"="Transparent"}
         LOD 100
 
         Blend SrcAlpha OneMinusSrcAlpha
 
         CGPROGRAM
 
         //the shader is a surface shader, meaning that it will be extended by unity in the background to have fancy lighting and other features
         //our surface shader function is called surf and we use the standard lighting model, which means PBR lighting
         //fullforwardshadows makes sure unity adds the shadow passes the shader might need
         #pragma surface surf Standard fullforwardshadows
         #pragma target 3.0
 
         sampler2D _MainTex;
         fixed4 _Color;
 
         half _Smoothness;
         half _Metallic;
         half3 _Emission;
 
         float3 _FresnelColor;
         float _FresnelExponent;
 
         //input struct which is automatically filled by unity
         struct Input {
             float2 uv_MainTex;
             float3 worldNormal;
             float3 viewDir;
             INTERNAL_DATA
         };
 
         //the surface shader function which sets parameters the lighting function then uses
         void surf (Input i, inout SurfaceOutputStandard o) {
             //sample and tint albedo texture
             fixed4 col = tex2D(_MainTex, i.uv_MainTex);
             col.a = 0;
             col *= _Color;
             o.Albedo = col.rgb;
 
             //just apply the values for metalness and smoothness
             o.Metallic = _Metallic;
             o.Smoothness = _Smoothness;
 
             //get the dot product between the normal and the view direction
             float fresnel = dot(i.worldNormal, i.viewDir);
             //invert the fresnel so the big values are on the outside
             fresnel = saturate(1 - fresnel);
             //raise the fresnel value to the exponents power to be able to adjust it
             fresnel = pow(fresnel, _FresnelExponent);
             //combine the fresnel value with a color
             float3 fresnelColor = fresnel * _FresnelColor;
             //apply the fresnel value to the emission
             o.Emission = _Emission + fresnelColor;
         }
         ENDCG
     }
     FallBack "Standard"
 }