MySQL Integrative PHP Form Development

I am in need of an experienced PHP developer to improve my existing project. I already have a project that involves a PHP application with 3 database-linked forms but require further enhancements for it. The ideal candidate should have a strong background in PHP, particularly in creating data-driven applications that interact with MySQL databases as this is what the project entails. Unknown functionalities are yet to be determined for the 3 forms as I have not specified whether their purpose is for data retrieval, modification or submission. As such, I would appreciate a candidate who has vast knowledge in these areas to guide the development and application of these functionalities within the project. Your expertise in recommending and implementing the most efficient and effective way to achieve the desired result will be a valuable asset to this project. Error picture attached. However in the same form add row also not working