Blucube

If your site has an SSL certificate you might find that you can access the site via both SSL (https) and non-SSL (http) URLs. This is a bad idea for security, and for SEO, as it can look like duplicate content on different URLs.
The answer to this is to redirect requests to non-SSL (http) URLs over to their SSL (https) equivalents using something called a 301 redirect. This tells the client (and search engines) that the resource they are looking for should always be accessed over SSL. This plugin offers two methods to achieve this:
<ul>
<li>By intercepting WordPress pages at header time, and if they are not already being requested over HTTPS sending a 301 redirect header, or</li>
<li>By adding mod_rewrite rules in the .htaccess file to redirect all requests to their HTTPS equivalents using 301 redirects.</li>
</ul>
Optionally, this plugin can also set <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security" rel="nofollow ugc">HSTS</a> headers for you, and make sure that all requests use the same hostname (i.e. fixing the issue where many sites can be accessed using both www. and non-www. URLs).

Simple SSL Redirects

Lightweight plugin to ensure access via SSL/HTTPS. Uses 301 (permanent) redirects for SEO benefits. Optionally sets HSTS and forces canonical domain.

WP Fix It - WordPress Experts

WP Fix It Easy Security Headers adds a simple page under Tools → Security Headers where you can toggle common HTTP security headers:
<ul>
<li>Strict-Transport-Security (HSTS)</li>
<li>Content-Security-Policy (CSP)</li>
<li>X-Frame-Options</li>
<li>X-Content-Type-Options</li>
<li>Referrer-Policy</li>
<li>Permissions-Policy</li>
</ul>
On activation, all headers are enabled by default and you’re redirected to the settings screen.
For convenience, the page and the Plugins screen include a “Check Headers” button that opens SecurityHeaders.com with your site’s URL prefilled (built dynamically from <code>home_url()</code>).
<h3>Notes on CSP</h3>
This plugin ships with a permissive default CSP intended to “work everywhere” out of the box (allows most external sources and inline code). For stronger protection, you should harden the directives for your specific site.
<h3>Key Features</h3>
<ul>
<li>One-click toggles for popular headers</li>
<li>Dynamic “Check Headers” scan link</li>
<li>Uses the WordPress Settings API (nonce + capability checks)</li>
<li>Output escaping and sanitization following PHPCS</li>
</ul>

Fix It Easy Security Headers

Configure core HTTP security headers for your WordPress site in a few clicks.

Simple SSL Redirects vs Fix It Easy Security Headers