Add Bearer token in header of a Swagger request

SwaggerUIOAuth2HeaderStartup.cs

public void ConfigureServices(IServiceCollection services)
{
    services
        .AddSwaggerGen(c =>
        {
            c.OperationFilter<AddAuthorizationHeaderParameterOperationFilter>();
        });
}

/// <summary>
/// Add auth header in your request middleware
/// </summary>
public class AddAuthorizationHeaderParameterOperationFilter : IOperationFilter
{

    public void Apply(Operation operation, OperationFilterContext context)
    {
        if(operation.Parameters == null)
        {
            operation.Parameters = new List<IParameter>();
        }
        operation.Parameters.Add(new NonBodyParameter
        {
            Name = "Authorization",
            In = "header",
            Type = "string",
            Description = "access token",
            Required = false
        });
    }
}