What is the equivalent of WebForms in ASP.NET Core?

I am doing my final year project in Computer Science and the project is a system for managing a college, like openSIS, but using ASP.NET Core to build it.

I need help on how to Add, Update, and Remove data using regular HTML forms, such as via <form/> and <input type="submit"/>. I knew how to do this in WebForms, but not in ASP.NET Core.

What you're asking to do is possible "out of the box" with ASP.NET Core and does not require a third-party solution.

Solution #1: ASP.NET Core Razor Pages

Microsoft - Introduction to Razor Pages

This is probably the most direct approach with the least to learn, and it is the modern equivalent to "Classic ASP.NET Web Forms." You are probably asking about this:

The basic idea is you create an "ASP.NET Core Web Application" project in Visual Studio and select the "Web Application" project template (confirming that ".NET Core" is selected in the template selection dialog before you click OK.)

You can then add "Razor Pages" containing HTML, CSS, and JavaScript, and use a simple post-back method via a regular HTML Form with a Submit Button. The link above has a topic on doing just that.

Solution #2: ASP.NET Core MVC

Microsoft - Overview of ASP.NET Core MVC

This is the second-most direct approach but does require you to grasp MVC concepts: Models, Views and Controllers. Implementing Razor Pages would only require you to grasp HTML and Razor Page code-behind, however, MVC as a pattern will provide your resulting project with a more maintainable and testable approach to the project.

The basic idea is to scaffold an "ASP.NET Core Web Application" project in Visual Studio, then select the "Web Application (Model-View-Controller)" project template.

Instead of adding Pages you add Views, to do anything useful these Views will have corresponding Controllers. There will also be Models defined, as you would see in a Razor Pages solution. In the case of MVC the Models are posted to your Controllers via Actions.

The link above covers the subject in detail, and there are numerous Stack Overflow posts on general MVC concepts.

Solution #3: RESTful Web APIs and Client-Side JavaScript

Microsoft - Building Web APIs

This is probably the least direct and most-technical approach. You will want to be familiar with "JavaScript" and "XHRs", "JSON" (or XML, but JSON has become de facto), and you will want to be versed in what it means to be a "RESTful Web Service" ie. that HTTP supports basic verbs to POST, GET, and DELETE a resource.

The basic idea is you create an "ASP.NET Core Web Application" project in Visual Studio using the MVC scaffold. You then implement Controllers to behave as RESTful web services. You can add Razor Pages and/or MVC Views to deliver the HTML and JavaScript.

With this approach you can create "Single-Page Applications" that never need to reload, where the HTML and JavaScript for the entire application can be delivered up-front and then RESTful web services used to modify the UI at the client. This can get advanced, and most developers will want to look into using a client-side templating engine. The leanest and simplest to use is probably going to be KnockoutJS, but others are more popular (and more complex.) Knockout has the value of solving a very specific problem: data-binding an HTML UI to JavaScript objects.

Regardless of the approach you take, start here: Microsoft - Get Started with ASP.NET Core