Welcome to the ODK forum, @Bharath! We're glad you're here. When you get a chance, please Introduce yourself here! I'd also encourage you to add a picture as your avatar because it helps build community
In the settings for Collect you can hide buttons from the main screen using the Main Menu Settings. You cannot rename them.
The configuration of the app name and icon is not something that is possible with default Collect. You would need to fork the project, change the code, and then publish the new app on your own Google Play Store Developer account. But you can create a custom “start screen” for your survey forms. See this example: start_screen.xlsx (11.4 KB)
To test the example, you will need to download the below image and save it as hands.png