Here’s how to turn Reading Mode on and off.
Reading Mode is only available in the Safari web web app.
How Do I Turn on Reading Mode on My iPhone or iPad?

The steps to turn on Reading Mode (aka Reader) are the same on the iPhone and iPad.
When the page has loaded, the address bar may displayReader Available.
If so, tap it.

Reading Mode is not supported by all websites.
So, this prompt may not appear.
If you don’t tap the Reader Available text before it disappears, tapaAin the menu bar.
TapShow ReaderorShow Reader View.
The page reformats to a high-contrast, reading-friendly version.
You’re now in Reading Mode.
you’re able to control how Reader looks to better match your preferences.
To do this, enter reading mode and tapaAin the address bar.
These parameters persist across other Reading Mode sessions until you change them.
How Do I Get My iPhone or iPad Out of Reading Mode?
Just tapaAin the address bar and then tapHide ReaderorHide Reader View.
This returns you back to the standard view of the web page.
Is There a Reading Mode on iPhone or iPad?
The iPhone operating system (iOS) has supported a reading-centric view in Safari for many years.
Over time, it’s been added to the iPad and Mac.
Right-hit the one to delete, and then selectRemove Item.
In the same menu, you might selectClear All Itemsto delete the entire Reading List.
On the iPad, go for the menu in the top left and then selectReading List.
Swipe left on a link to remove it, or chooseEditto pick multiple sites.
Sites compatible with Reader Mode will display articles with a dark background when this setting is on.