How to Fix Pages That Have No Viewport Tag
This is a fairly rare issue. It’s important. If you ever come across it, you should fix it and you should fix it as soon as you can, but it’s also very easy to fix and I’ll show you how.
So the first thing you’ll want to do is log into your WordPress admin dashboard. Look on the left-hand side for appearance and scroll over or click, and then go to your theme editor.
Then over on the far right side, find a file called header.php. It will usually be called theme header, although depending on your theme, it might have a different name, what you want to look for is in parentheses right below the name, it should say, header.php, click on that.
And that will update this text here in the middle. Now that viewport tag should come probably first, right after the head tag and what it does is it basically tells, when a browser opens up your webpage, no matter what device that’s on, whether it’s a phone or tablet or desktop, it tells it how many spaces it should take up.
And that’s usually going to be the full width. So if you can just copy and paste this exact line right after the head tag, if it’s not already there, then click to update your file and you should be all set.