For iOs 14 need which versio of Xcode.

Xcode 14 incorporates Quick 5.7 and SDKs for iOS 16, iPadOS 16, tvOS 16, watchOS 9, and macOS Monterey 12.3. The Xcode 14 delivery upholds on-gadget troubleshooting in iOS 11 and later, tvOS 11 and later, and watchOS 4 and later.Xcode 14 requires a Macintosh running macOS Monterey 12.5 or later

Do you want to make an app that will run on iOS 14? If not, what do you mean by "need for iOS 14"?

If you just want to make an app that will run on iOS 14, you can use the latest version of Xcode. Set the deployment target for the app target to iOS 14. Take the following steps to set the deployment target:

1. Open the project editor by selecting the project file from the left side of Xcode's project window.
2. Select the app target from the Targets list on the left side of the project editor.
3. Click the General button at the top of the project editor.
4. Choose iOS 14 from the menu in the Minimum Deployments section.

The following article has more detailed information on supporting older versions of iOS:

Supporting Older Versions of iOS and macOS