<div class="footer">
  {{if isset .Site.Params "FooterMsg"}}
  <p>{{.Site.Params.FooterMsg}}</p>
  {{else}}
  <p>Powered by <a href="http://gohugo.io">Hugo</a>. This theme—Slim—is open sourced on <a href="https://github.com/zhe/hugo-theme-slim">Github</a>.</p>
  {{end}}
</div>

<div class="footer">
  {{ if isset .Site.Params "FooterMsg" }}
  <p>{{ .Site.Params.FooterMsg | safeHTML }}</p>
  {{else}}
  <p>Powered by <a href="http://gohugo.io">Hugo</a>. This theme—Slim—is open sourced on <a href="https://github.com/zhe/hugo-theme-slim">Github</a>.</p>
  {{end}}
</div>

Allow FooterMsg to use HTML
Allow FooterMsg to use HTML

Can set href link in footermsg.