No credentials needed for Sqlite database?

I am not quite getting the idea of sqlite database. I am developing a hybrid mobile app using Ionic Framework and backend with PHP.

I referrred to this article for using the sqlite https://blog.nraboy.com/2014/11/use-sqlite-instead-local-storage-ionic-framework/

I have a few questions now,

1) So, anybody can create a table,insert and do any kind of operations? Is'nt there any need of a security method to access the DB like mysql?

2) Is a separate instance of Sqlite created for each application? Coz if not,I can make a guess for a tablename created by any other application and delete it all together,isn't it? I just dont get it?

1) SQLite is a file database so if you have access to file you have access to database and can do anything with it. What is the purpose of restricting access to db when you can just delete whole file? SQLite db file should be created in app private storage so no one have access to it only your app.

2) the answear is above. just create file in right place and everything will be fine :)

1) So, anybody can create a table,insert and do any kind of operations? Is'nt there any need of a security method to access the DB like mysql?

By default, each app db will store in their private folder(data/data/your_package_name/database and only that app or system app can access to it.
But if you choose to store your db in sdcard, anybody can mess up your db if they know the path to db file and have right to access it.
Other case is if your device is root, other apps can access your db too.

2) Is a separate instance of Sqlite created for each application? Coz if not,I can make a guess for a tablename created by any other application and delete it all together,isn't it? I just dont get it?

Like above, each app can choose where to store their db file, so basically, they a separate instance.
You can also create multi db file for one app if you like.