I am planning to get beginners linux shared hosting for my custom android App. I want to know is mysql database are accesible from outside website like desktop software for management and If i can connect my custom app.
This depends on many factors. Here's your list of things to check.
1) Does whatever account/service you've purchased from GoDaddy allow this.
2) Setup credentials (db host/name/user/pass) for you to access your database. The dbhost in this case will be the IP where you're connecting from.
3) Warning: This should only be done over SSL, which means...
4) You must setup MySQL/MariaDB SSL connections, if your account/service allows this.
In general, if you're writing a hobby app then GoDaddy hosting may be sufficient.
If you're writing an App you expect to succeed wildly + generate your income, then best look at dedicated hosting + hire an admin.