I want to download Facebook and is not

Here are a few general steps you can try to resolve the issue:

1. Check internet connectivity: Make sure that you have a stable and active internet connection on your device. Without an internet connection, you won't be able to download apps from the App Store.
2. Restart your device: Sometimes, restarting your device can help resolve temporary glitches or issues. Try restarting your device and then attempt to download the Facebook app again.
3. Clear App Store cache: Clearing the cache of the App Store can help refresh the store and potentially resolve download issues. Go to the App Store, tap on your profile icon, scroll down to find the "Clear Cache" option, and select it. Afterward, try downloading Facebook again.
4. Check available storage space: Make sure that you have enough free storage space on your device to install the Facebook app. If your device is running low on storage, it might prevent app downloads. Delete any unnecessary files or apps to free up space.
5. Reset network settings: If the above steps didn't help, you can try resetting your network settings. Go to "Settings," select "General," choose "Reset," and then tap on "Reset Network Settings." Keep in mind that this will remove saved Wi-Fi passwords, so you'll need to reconnect to Wi-Fi networks afterward.

See: If you can’t download or update apps on your iPhone or iPad - Apple Support

If you are still experiencing this issue after following these steps you should contact apple support.