How can I backup my delete msgs from iCloud

I don't know if this can solve it and if it's your case but...

Recover a recently deleted message or conversation

When you delete a message or conversation, it’s moved to the Recently Deleted folder. You can view and recover items in the Recently Deleted folder for up to 30 days. After 30 days, the messages are removed from all your devices. After 40 days, the messages are permanently deleted from iCloud.

1. In the Messages app  on your Mac, choose View > Recently Deleted.
2. If you don’t see Recently Deleted, you may not have deleted a conversation within the last 30 days.
3. Select the conversation in the sidebar.
4. Do one of the following:

• • Recover a recently deleted message or conversation: Click Recover.
  • Permanently delete a recently deleted message or conversation: Click Delete.

If you sync messages, with iCloud, once you delete them, they are gone. iCloud is NOT a backup service as in an actual archival backup. iCloud is a syncing service.

In the case of the OP, they asked how to back up messages from iCloud, which they have deleted already. It's too late to backup what has already been deleted.

This is factual. And I should have asked the OP if they have Messages turned on in Settings > Their Name > iCloud > Messages.

If they do, they're messages are NOT contained in a iCloud backup. So, backing them after they were deleted would be impossible. If however, Messages are NOT turned on in iCloud AND they have a backup made from before they deleted the messages, it would be possible to restore an older backup to their phone, which would contain messages, but NO messages sent or received after the backup was made.

All said, if they sync messages with iCloud, they simply cannot back them up after they were deleted. And that's fact. And also note the OP didn't ask how to restore messages (though perhaps that's what they were hoping to accomplish), they asked how to backup messages which were deleted.

Kind of too late to back them up if you've deleted them already.

What iCloud Backup includes

Your iPhone and iPad backups include all the information and settings stored on your device that don't already sync to iCloud.

Device settings, Home Screen layout, and app organization

When you restore from an iCloud backup, things like your device settings, your Home Screen layout, and app organization are also restored. 

Other on-device information

Any purchased Ringtones and your Visual Voicemail password (which requires the SIM card that was in use during backup) are also included in your iCloud Backup. 

Apple Watch backups 

Your Apple Watch backup is included in the backup of your iPhone or iPad.

Photos, videos, messages, and app data

If you don't use services like Messages in iCloud or iCloud Photos, the information below is stored in your iCloud Backup to ensure that it's also protected. 

Another user that can't scale images to be used in a newsgroup. You need to resize them, otherwise some people won't be able to read them. And understand why you can't recover deleted messages from the icloud

Not true if you have iCloud your messages will be backed up

You are wrong and you also told me wrong stuff about my iphone

I'm not going to argue with you. Please provide detailed instructions on how the OP can backup messages from iCloud, they have already deleted.

Setting iCloud backup

What does this have to do with the topic of this discussion thread?

Yes I think a visual Apple guide for iCloud deleted messages would be more effective

Thanks for posting this. I should have told the OP to check their recently deleted folder to see if the messages were there.

you're welcome :)