Your First Add-in: Travel Request site columns

Elements.xml

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Field Type="Choice" 
         DisplayName="Travel Request Status"
         Required="FALSE"
         Format="Dropdown"
         FillInChoice="FALSE"
         Group="Travel Request"
         ID="{c33db2b3-0af9-4f5a-bbbe-fa60739aff94}"
         Name="TravelRequestStatus">
    <Default>DRAFT</Default>
    <CHOICES>
      <CHOICE>DRAFT</CHOICE>
      <CHOICE>Approved</CHOICE>
      <CHOICE>In Progress</CHOICE>
      <CHOICE>Rejected</CHOICE>
    </CHOICES>
  </Field>
  <Field Type="Text"
         DisplayName="Request Number"
         Required="FALSE"
         Group="Travel Request"
         ID="{bbd79258-7ba1-4a48-acbb-1f7de3b385cb}"
         StaticName="RequestNumber"
         Name="RequestNumber"></Field>
  <Field Type="Boolean"
         DisplayName="Urgent"
         Group="Travel Request"
         ID="{7df4e16c-5fa1-4b4d-9c7e-49b717ca866f}"
         Name="Urgent">
    <Default>0</Default>
  </Field>
  <Field Type="Note"
         DisplayName="Visiting Contact Details"
         Required="TRUE"
         NumLines="6"
         RichText="FALSE"
         Sortable="FALSE"
         Group="Travel Request"
         ID="{7d8cc55e-241d-4a18-b6c9-4031059b5dbc}"
         Name="VisitingContactDetails"
         RestrictedMode="TRUE"
         RichTextMode="Compatible"
         IsolateStyles="FALSE"
         AppendOnly="FALSE"
         UnlimitedLengthInDocumentLibrary="FALSE"></Field>
  <Field Type="Note"
         DisplayName="Pickup Address"
         Required="TRUE"
         NumLines="6"
         RichText="FALSE"
         Sortable="FALSE"
         Group="Travel Request"
         ID="{82d0de93-3d28-4120-8095-df3fefd38a98}"
         Name="PickUpAddress"
         RestrictedMode="TRUE"
         RichTextMode="Compatible"
         IsolateStyles="FALSE"
         AppendOnly="FALSE"
         UnlimitedLengthInDocumentLibrary="FALSE"></Field>
  <Field Type="Note" 
         DisplayName="Destination Address"
         Required="TRUE"
         NumLines="6"
         RichText="FALSE"
         Sortable="FALSE"
         Group="Travel Request"
         ID="{270ae570-7c56-413b-b0a0-2908c3a79eb7}"
         Name="DestinationAddress"></Field>
  <Field Type="Note"
         DisplayName="Pickup Address"
         Required="TRUE"
         NumLines="6"
         RichText="FALSE"
         Sortable="FALSE"
         Group="Travel Request"
         ID="{82d0de93-3d28-4120-8095-df3fefd38a98}"
         Name="PickUpAddress"
         RestrictedMode="TRUE"
         RichTextMode="Compatible"
         IsolateStyles="FALSE"
         AppendOnly="FALSE"
         UnlimitedLengthInDocumentLibrary="FALSE"></Field>
  <Field Type="DateTime"
         DisplayName="Pickup date and time"
         Required="TRUE"
         Format="DateTime"
         Group="Travel Request"
         FriendlyDisplayFormat="Disabled"
         ID="{e0c7133c-a908-48ef-a3e6-5cb6047579eb}"
         Name="PickupDateAndTime" 
         CalType="0"></Field>
  <Field Type="Note" 
         DisplayName="Reason for Trip"
         Required="TRUE"
         NumLines="6"
         RichText="FALSE"
         Sortable="FALSE"
         Group="Travel Request"
         ID="{7c265805-c570-403a-90ac-1eca2944c5a7}"
         SourceID="{119a0d9a-22d9-4814-b4b1-458f382c91a0}"
         StaticName="ReasonForTrip"
         Name="ReasonForTrip"
         RestrictedMode="TRUE"
         RichTextMode="Compatible"
         IsolateStyles="FALSE"
         AppendOnly="FALSE"
         UnlimitedLengthInDocumentLibrary="FALSE"></Field>
</Elements>