After I jailbreak my iOS device, is it still able to get updates?
A jailbreak is specific to a single iOS version or group of versions. You can always update your iOS device, but if you update to a version without a jailbreak available, you won't be able to jailbreak.

For example, the latest unc0ver jailbreak at the time of writing supports iOS 11.0 to 12.4. When iOS 13 is released, you will still be able to update your device to this version, but the jailbreak will not be available, since the system partition is reset. Then when a jailbreak is released for iOS 13 you can jailbreak once again.