<PackageReference Include="FastReport.Web" Version="*" />

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    ...
    app.UseFastReport();
    ...
}

public IActionResult Index()
{
    var webReport = new WebReport();
    webReport.Report.Load("path/to/report.frx");

    return View(webReport);
}

@model FastReport.Web.WebReport

<div>
    @await Model.Render()
</div>