Open the App Store and install an app for sticker creation (e.g., Sticker Maker, Canva, or an iMessage sticker app).
Open the sticker app.
Choose to create a new sticker (or start a new project).
Add your image:
Upload from Photos, or
Take a photo, or
Import from files.
Crop/adjust the image to fit the sticker.
Remove the background (if the app offers a background remover) or use cutout tools.
Add effects/text (optional).
Save/export the sticker in the app.
Add the sticker to iMessage:
Look for “Add to iMessage” or “Export to Stickers.”
Confirm when prompted.
Open Messages on iPhone.
Open a chat.
Tap the App Drawer (left of the text field).
Select the Stickers app.
Find your new sticker and tap to send.