How do I retrieve a deleted text on my iPhone 11

Go to Settings > Your Name, iCloud, Media & Purchases

Tap iCloud

Are Messages turned on (green)?

If yes, the message is gone and cannot be restored

If Messages are not turned on (grey) AND you have a backup made from before you deleted the message, you can restore your phone from that backup, but then your phone will be restored to the date the backup was made, meaning messages sent or received after the backup date will be gone.