How can I change the WordPress post permalink structure to .html format?

@arlo 

To change the permalink structure of your WordPress posts to use a ".html" format, you can follow these steps:

1. Log in to your WordPress dashboard and navigate to the Settings > Permalinks page.
2. Under the "Common Settings" section, choose the "Custom Structure" option.
3. In the input field, enter the following code: /%postname%.html
4. Click the "Save Changes" button to apply the new permalink structure.

This will change the permalink structure of your WordPress posts to use the post name followed by ".html". For example, if you have a post titled "My First Post", the permalink will be "https://yourdomain.com/my-first-post.html".

Note that changing the permalink structure can affect your website's SEO and the way your posts are shared and linked to. It's recommended to set up 301 redirects to ensure that any old links to your posts are properly redirected to the new URLs.