Is there is a way to add Frame,Textlabel To CoreGui?

Here's an answer by M39a9am3R to the same question:

CoreGui is not accessible by normal scripts. CoreGui is often changed by exploits or while in studio through a plugin, however, the latter doesn't transfer over to the game. Might I suggest looking into the ResetPlayerGuiOnSpawn Property

That ResetPlayerGuiOnSpawn property is now deprecated though. Use this one instead.

Here's a link to the thread for reference.

Hope this helps! :)