Redirection is the process of redirecting one URL to another it can be a 404 page, old URL, http to https or non-www to www, it depends on the website.
Here discussed about http to https and www to non-www redirection.
Search engines have their own algorithms that counting one www and non-www URL as a two different URL that means it would read www and non-www as two versions of one website. For example, if example.com is not redirected to www then the search engine will read two versions first one www.example.com and second example.com. So these two versions display two copies of URLs and contents and that is how it is generating a negative effect on the search engine’s mind.
Same as for http to https redirect, it is also important as it will generate two versions of one website and count two different pages. So finally, to get away from the negative effects of search engines it would be essential to redirect the website to one specific URL.
In the above redirection generator tool, you can paste the URL and check whether it is redirected or not.
How to redirect website http to https .htaccess?