How do I get a full screen preview for my iPad?

Hello yi-ren,

Thanks for using the Apple Support Communities. We understand that you're wanting to know how to view a full page when selecting a link sent to you in Messages. You should have two options for viewing links, if you perform a long press, you'll get the small pop-up box, however if you simply tap the link, it should open fully in Safari. Is this not occurring for you using those actions? If you're only receiving the small pop-up box, if you tap it, does that direct you to the full screen view in Safari?

Best regards.

Hello yi-ren,

Thanks for letting us know you're not getting the expected options for this feature. If you haven't done so, be sure to restart you iPad, to see if that helps. You may also want to try quitting the Messages app as well.

Restart your iPad

How to force an app to close on your iPhone, iPad, or iPod touch

Are you running the latest iPadOS version? You can check this in Settings > General > About.

Best wishes.

You have very likely managed to enable a Safari Slide Over view - this being a major multitasking feature of iPadOS, fully detailed in the iPad User Guide for iPadOS. 

Here is the easy way to change the Slide Over view, to full screen... 

Identify the small grey drag-bar at top-centre of the Slide Over window. Touch-and-drag the drag-bar to the top-centre of the screen - and lift your finger; the Slide Over window will transform into a full screen view.

You may find these overview Apple video guides to be helpful:

After viewing, you’ll be ready for the additional Multitasking Guide:

Use Multitasking on your iPad - Apple Support

The iPad User Guide for iPadOS is also a rich source of information. Here are links to both the downloadable and online versions of the Guide:

‎iPad User Guide on Apple Books

iPad User Guide - Apple Support

I hope this explanation and additional information is helpful in resolving any difficulties you may be having with Multitasking features of your iPad.