To delete stickers on an iPhone, you have two main options depending on whether you want to remove a sticker from a message or delete it entirely from your sticker library:

Delete a Sticker from a Message

1. In the Messages app, find the message with the sticker you want to delete.
2. Touch and hold the message bubble containing the sticker.
3. Tap Sticker Details.
4. Swipe left on the sticker you want to delete.
5. Tap the Delete button to remove the sticker from that message on your device (note: this only removes it for you, not the recipient)

Delete Stickers from Your Sticker Library

1. Open the Messages app and go to any conversation.
2. Tap the plus (+) icon next to the text input field.
3. Select Stickers to open your sticker gallery.
4. Make sure to select the tab showing your custom stickers (often the second tab from the left).
5. Press and hold the sticker you want to delete.
6. When the options appear, tap Delete to remove the sticker permanently from your library.
7. Repeat for any other stickers you want to remove

Alternatively, you can access your stickers via the Emoji keyboard:

• Tap the Emoji icon on your keyboard.
• Switch to the "Live" tab (peeling sticker icon).
• Long press a sticker and choose Delete or use the Rearrange option to delete multiple stickers at once

This method works on iOS 17 and iOS 18 and later versions, with a simple long press on the sticker triggering the delete option

. In summary, long pressing a sticker either in a message or in the sticker gallery is the key action to reveal the delete option for removing stickers on an iPhone.