How to create database table, add data, update and delete using wpdb via plugins?

Yes, it is possible to add, update and delete data in custom tables with a plugin.

When you run your insert_data_into_table() function, what errors do you get?

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)