I need backup my deleted messages

If you back up your texts, you can restore the backup to recover the deleted texts assuming that the texts are in the backup. You will overwrite the current contents on the device when you restore the backup.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

If you sync texts with iCloud and you deleted them, you cannot recover them at all. iCloud is a syncing service, not off device storage so all that using iCloud with text messages does is to keep your messages in sync across all devices.