Hi there, Obuya1, welcome to the Community, and thank you for reaching out about your A03. I am sorry to hear of freezing when attempting to open Apps and Notifications. When your phone or tablet freezes or crashes, it can be really nerve-wracking. The good news is that this can probably be fixed without having to send your it in for service. Performing simple actions like rebooting and updating the software are just a couple of the things you can do to prevent freezes and crashes in the future: https://www.samsung.com/us/support/troubleshooting/TSG01001416/
As @VerbumVeritum also suggested, wiping the cache partition can help smooth out device behavior, so give that a try as well!
If the troubleshooting is not helpful, the phone will need to be evaluated by a certified technician. For service in the U.S., you can take the phone to a local U.S. walk-in service location https://www.ubreakifix.com/samsung or to ship the phone in for service, please reach out to us via one of the following options: 1. Facebook Messenger: http://m.me/samsungsupport 2. Twitter: https://twitter.com/messages/compose?recipient_id=18768513- 3. Private Message: https://bit.ly/3hzZfw8 If the PM link is not working for you, you can click on my name and send me a private message directly from my profile.
For service outside of the U.S., please use this link: https://www.samsung.com/us/common/visitlocationsite.html