Folders on iPhone desktop disappeared

Hello sandrafromambler,

Does that persist after restarting your iPhone using the steps below?

1. Press and hold the side button until the power-off slider appears.

2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.

3. To turn your device back on, press and hold the side button until you see the Apple logo.

You can also find those steps in this resource: Restart your iPhone - Apple Support

Should your folders still not appear on your Home Screen, you can use the steps from this resource to recreate your folders, if needed: Organize your apps in folders on iPhone - Apple Support

You may also be able to reinstate your folders by restoring from a backup: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Keep in mind that restoring from a backup would remove any data you've added to your iPhone since the backup was created.

Hopefully those resources help clarify your options.

Take care.