Which theme are you using?
Post the URL of your blog i will let you know simple way to do this using CSS code!
you appear to be using a commercial theme called perada. As this is a theme issue and support for commercial themes cannot be provide here, you need to use your vendor’s own support channel to ask about changing the post info output.
Adding the following CSS rule to your child theme or via a custom CSS plugin should visually hide your username:
.post-information .author {
display: none;
}
however the username will still appear in the page source, so this is not the best solution and is a workaround at best. There may be an option in your theme to change what information is output in the post-info, however support volunteers do not have access to commercial themes, so cannot provide that information but the vendor’s own support will know.