Hello, What is the version of Prestashop you are using?
And you just want to replace shipping cost with your custom price by typing in admin panel, Right?
I'm interesting in your project very well.
I'm good in C#, .Net Core, MVC, ASP.NET, Angular.js, Yii2, PHP, Laravel, Codeigneter, Wordpress, Open Cart.
I m quite well experienced in these jobs.
Let's go ahead with me.
Thanks