All Blogger blog used to have a same default 404 error page which never matches with your blog theme design. So with new Search preferences option in Blogger, Google also added an option by which now we can create our own custom 404 error page.
So if you are a designer (if you are not a designer then you can also just text) and want to have your custom 404 error page then here are the following steps:
- Go to Blogger in Draft dashboard
- From More option drop-down, select Settings
- Then click on Search preferences from left column
- Now edit and enable Custom Page Not Found option
- Their enter code of your design (it should not contain HTML, HEAD and BODY tags, if you are adding any CSS for the same then you need to write inline CSS or add CSS in style tag their only)
- Then click on Save change button
Now visit any page in your blog which doesn’t exist and you will able to see your custom 404 error page design which Google try to add your current template. If you see any problems in design then check and edit your code once again if there is any problem.