Nobody wants to see the standard Sitecore 404 page. Thankfully it's really easy to change the error pages a user is redirected to through some config settings.
Your error pages can be pages in Sitecore or static HTML files. For 404 pages I would normally use a Sitecore page, that way content authors can still manage its content. For an Error Page I would recommend a static html file to avoid issues with the Error page potentially error-ing.
Add these to a patch file and update the urls accordingly:
1<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">2 <sitecore>3 <settings>4 <!-- ITEM NOT FOUND HANDLER5 Url of page handling 'Item not found' errors6 -->7 <setting name="ItemNotFoundUrl">8 <patch:attribute name="value">/ErrorPages/404.html</patch:attribute>9 </setting>10 <!-- LINK ITEM NOT FOUND HANDLER11 Url of page handling 'Link item not found' errors12 -->13 <setting name="LinkItemNotFoundUrl">14 <patch:attribute name="value">/ErrorPages/404.html</patch:attribute>15 </setting>16 <!-- LAYOUT NOT FOUND HANDLER17 Url of page handling 'Layout not found' errors18 -->19 <setting name="LayoutNotFoundUrl">20 <patch:attribute name="value">/ErrorPages/404.html</patch:attribute>21 </setting>22 <!-- ERROR HANDLER23 Url of page handling generic errors24 -->25 <setting name="ErrorPage">26 <patch:attribute name="value">/ErrorPages/Error.html</patch:attribute>27 </setting>28 </settings>29 </sitecore>30</configuration>
These settings are already defined in the web.config file and changing them here will have the same effect, but I recommend adding patch config files as it will make your solution easier to update in the future.