It's recommended for all websites to use HTTPS - for both security and SEO reasons. If your WordPress website:
Doesn't load by HTTPS at all
Loads by HTTPS but the website looks "broken"
Then you need to change one setting in the admin dashboard.
NOTE:
Before proceeding, make sure you have an active SSL installation for this domain/subdomain. You can check this in the SSL section
Log in to your WordPress website's admin area. Check this article if you don't know how to do it.
Then, click on Settings in the left menu:
Your General settings will open up. You need to update URLs from HTTP to HTTPS in these two fields:
WordPress Address (URL)
Site Address (URL)
Save changes at the bottom of the page - your website should already load without issues by HTTPS 🚀
NOTE:
You can make your website load by HTTPS by default