How to save more important messages in iPhone to prevent accidental deletion?

One; Store in ICLOUD

Download a Baidu network disk and save it in this one.

After the screenshot, save it in the photos of Baidu's network disk, so that you can save more copies to prevent accidental deletion.

Second: If it is really secret information that needs to be saved, it is recommended to use iCloud cloud for backup. The iphone system comes with it and can be backed up at will.

Another is that you back up your mobile phone on iTunes on your computer.

There is no other way, just copy the message and save it in the memo.