How can I remove the page not found error: 404 in my blog?

Page not found error: 400 is a very common error encountered in the web space and the main reason for this is that if a resource is below the standard or quality then the hosting site removes it from the site but its link remains at so many places as that does not require to be removed. Now when someone clicks at that link then as the resource is not available then this message is presented on the screen as is a standard error presentation.
The only way to revive this situation is to request the site for undeleting it and bringing back by unlocking it for editing and if the request is agreed by them then one can improve that and then resubmit for consideration.

What Is Error code 404: It is an HTTP status code.
When this message will come.
1. When content is transferred from one URL to another URL
2. When the URL content is removed without adjusting any internal links
3. When the URL was wrongly written or linked wrongly or typed into the browser wrongly.
4. When there is some problem with the server or when the connection is interrupted
5. domain name may not exist

You can find out any such pages are existing on your blog by using
1. Google Search Console
2. Dead Link Checker
3. W3C Link Checker

As a blog owner, once in a while, you have to check the blog for error pages using one of the above tools and find out them and fix the problem.
The best thing is to have your design for the error page and you should see that there will be an internal link on this page that will take the viewer to your home page or any other pages where some good content is available.

Error: 404 is the part of any website when we create any website or blog we link one URL to another. But sometimes we forget to post the Correct format of URL or we post deleted URL.
To Remove Error: 404 You need to follow a few steps as mentioned below
Check the URL link from the address bar.
Search your page from a popular search engine like Google or Bing
Clear your browser's cache.
Check the DNS servers
You can check your own website through tools like DeadLinkChecker.com and ATOMSEO.
If you use WordPress, You need to check permalink issues, Fix broken links for pages or posts through the WordPress dashboard. If found mistakes then correct and update permalink settings

If you remove any existing page in your blog, then only Error 404 will come. It doesn't affect your search engine ranking of your blog. It will go away by time as eventually deleted link will de-index from search engines.

Suppose, if you make any broken link in your blog, you can repair it and make it working. So overall, you don't need to worry about if error 404 comes.

You can consider setup the 404 page error with more info like visit home page or other useful resources and visitors will stay back to your blog. You should design your error page in your site theme.

Yes, it is a common error. This happens due to content not matching with your page URL or after submission of post you have changed your Title. There are two remedies to resolve your 404 error: Redirect and Removal.
Assuming your blog is in blogspot.com

1. Redirect the error page to your Blog Home page--

To solve the issue you have to follow the below-given steps
Sign in to your blog and go to the setting page, then you find "Errors and redirects" under which you click the Custom redirect button. Here you will find "From"-- and in the below a " to"-- button.
Now copy the page URL after"/"of the 404 page. Like if your URL of the error pages is "https://XYZ.blogspot.com/2022/023/how-to-improve.html" then copy only "/2022/023/how-to-improve.html"
and past this in the "from" field as shown above and in the "to" field" just remove the one slash" /" by keeping another / only in that field. Now you will find there save button, you can click permanent to fix it permanently. Then try to check it by clicking the error page again you will find the home page.

But Removal of the page is not recommended because the page already exists.
However, to remove the page from google you have to go to the google search console pages after signing your blog.
You will see the index menu and under this, there is a crawl error menu, click it then past the URL of the error page under the temporary hide section. Then mark it as fixed. You will be done.
I think from the above it is clear now and you will be able to resolve the problem.

A 404 message denotes Hyperlink Transfer Protocol status code indicating that server could not locate the website. It also signifies that your web browser can connect with the server but the page you are trying to locate cannot be reached at. There are other HTTP errors but 404 is the most common.
It is very likely that the page might have been removed and is appearing to a new browser.
The following steps will be helpful in resolving this issue-
1) Redirect the page - The most convenient way to fix 404 error is to redirect the page to another one using a 301 redirect. A 301 is a response code signalling to a user's browser that your content has been moved to a new URL.
2) Correct the link - We all are humans and errors can happen from our sides at any stage while creating a hyperlink. If such is the case, go back and fix the URL.
3) Restore the deleted page - It is desirable for the industrial companies to update continually and fine tuning their websites even deleting a page. However, just because you have removed a page from your site, it does not mean that people are unable to search the same. While deleting the pages, ensure to redirect these to the pages with the similar contents.