First, we can tell you that iTunes no longer exists. So when you upgrade to macOS Catalina, the iTunes application will be removed from your system. And also, it's hard to say if someone will miss him, since he didn't age well and the users got tired of his slowness. Having said that, iTunes had a very important job; and it was to make a backup of your iPhone or iPad.
It also allows you to restore your iOS device from a previous backup, which makes you wonder how this will work with Catalina. The answer is in the Finder application. This is how you can make a backup of an iOS device in macOS Catalina.
Backup in macOS Catalina
First, start Finder and connect your iPhone to your Mac. In the left column, you'll see that the device appears below your MacBook. You must select it.
In the preview pane on the right, click the "Pair" button. You must allow your Mac to access the files on your iPhone, and permission must be granted to your mobile. Now unlock it, allow your Mac to access from the pop-up window in enter your access code if requested.
Once your Mac has access to your iPhone, the preview panel will be replaced with a familiar interface; the iTunes device details interface, with some changes.
Of course, this is not iTunes. Apple has just designed the new feature after iTunes to make it easier to use. Now, select the "General" tab and click on the "Synchronize" button at the bottom. Allow it to backup your data and synchronize it with your Mac.
There are some details with the new function
This is how it works in the public beta version of Catalina. There is a rather notable deficiency; and is that Finder does not indicate that the backup is complete or in progress. Also, the sync button appears shaded and cannot be used. But there is no progress bar or anything like that.
Now, to check if your mobile is still syncing, look at the status bar for the sync icon. Once the synchronization is complete, the “Synchronize” button will be clicked again. Also, no notification is shown when synchronization is complete.
To restore your iPhone, you will always do what you have always done, but with some minor modifications. Put the iPhone into restore mode, connect it to your Mac and select the device inside the Finder. Once selected, you will see an option to “Restore iPhone” as it was in iTunes.
With regard to the selection of what is synchronized with your iPhone, the same options that iTunes had to offer are in Finder. You must see through the different tabs under your device; Music, Movies, TV Shows, Podcasts, Audiobooks, Books, Photos, Files and Information, to select what to synchronize.