some steps on how to add a URL clickable link into the 'More Information' panel for the IIIF UV viewer 

1. go to 'Deposits | Advanced Tools | delivery XSL files'

2. edit the mets2manifest.xsl file (recommend that you keep a copy somewhere else just in case)

3. add the following variables -- just to make life easier 

  <!-- facebook variables -->
  <xsl:variable name="FACEBOOK_HEAD">&lt;a href=&apos;</xsl:variable>
  <xsl:variable name="FACEBOOK">https://www.facebook.com/sharer/sharer.php?u=</xsl:variable>
  <xsl:variable name="FACEBOOK_END">&apos;&gt;Share with Facebook&lt;/a&gt;</xsl:variable>

4. add the folowing - as each IE requires a 'Title', I set up the facebbook link so that it i generated based on a title.

    <!-- start Facebook section -->
    <xsl:for-each select="/mets:mets/mets:dmdSec[@ID=$IE_DMD_ID]/mets:mdWrap/mets:xmlData/dc:record/dc:title |                        /mets:mets/mets:dmdSec[@ID=$IE_DMD_ID]/mets:mdWrap/mets:xmlData/dc:record/dcterms:title ">                                                      {                                                                

      <xsl:variable name="URL_STRING " select="concat($FACEBOOK_HEAD,$FACEBOOK,$Handle,$FACEBOOK_END)" />
      <xsl:variable name="URL_STRING1 " select="encode-for-uri($URL_STRING)" />
      <xsl:value-of select="$LABEL" />&quot;,  <xsl:value-of select="$VALUE" />
      <xsl:value-of select="$URL_STRING " />&quot;                                              

                            }                                                                            

      <xsl:if test="position()!=last() or count(//dc:title) &gt; 0 or count(//dcterms:title) &gt; 0">, </xsl:if>
    </xsl:for-each>
    <!-- end Facebook section -->