To get the Combine Images shortcut, you have to allow shared shortcuts.
Go to your iPhone’sSettingsand tapShortcuts.
Tap to toggle onAllow Untrusted Shortcuts.

Note
If you’re unable to do this, you’ll have to run a shortcut first.
Go to theShortcutsapp and selecta shortcutto run quickly.
Then repeat steps 1 and 2.

TapAllowand type your passcode to confirm.
Navigate to theCombine Imagesshortcut web page to automatically open it in the Shortcuts app.
Scroll down to the bottom of the page and tapAdd Untrusted Shortcut.

TapMy Shortcutsin the bottom menu.
Tap the newly addedCombine Imagesshortcut followed byOKto run it.
Tap to selectthe photosyou want to combine.

A blue checkmark will appear in the bottom right of every photo you’ve selected.
TapAddin the top right corner.
choose the order in which you want the photos to appear by tappingChronologicalorReverse Chronological.

Customize the image spacing by enteringa numberand tappingDone.
If you don’t want space between the images, leave it at 0.
TapDonein the top left.

It’s a great alternative if you’d prefer not to use the Shortcuts app method discussed above.
Download thePic Stitch appfrom the App Store.
Tap any section of the layout to prepare to add a photo to it.

Tapthe photosyou want to add and then tapDonein the top right.
Drag and dropa photointo its appropriate frame in the combined photo layout.
TapDonein the top right when you’re finished editing.
Repeat step five for the remaining photos and frames.
TapSavein the bottom menu to save it to your camera roll or share it directly to social media.
Any one of thesefree photo editing appsshould do the trick.
You’re not limited to apps when it comes to combining photos.
There are plenty of free photo collage makers available online.
Check out BeFunky, Canva or another one of thebest free online photo collage makers.
Combine photos on Android by downloading the Image Combiner app.
TapAdd Pictureto add the photos you want to combine or tap thehamburger iconand selectGalleryto get to your photos.
After you choose the ones you want, tap the check mark and selectCombine Imagesin the app.