Dear Brindha,
Greetings of the day

What do you mean by "text about the background" ?

In custom splash screen you can define various size images to support for each environment (i.e. Android / iOS).
Here you can not define any custom texts or styles because this will be loaded before you load your application.

You can check detailed documentation already available in this link related to custom splash screens.

If this doesn't answer your question, kindly provide more details and try to demonstrate your issue with a sample image or sample application so that we can understand and suggest better solution.

Regards,

Palak Patel