How to create pdf/excel without saving in server path

Question

I have a Web API project which is developed by C# that is running on a server, and my Client technology is developed by Angular 2. Now, I have a requirement of doing Reports, I am not clear where to create the PDF/excel whether in Server or Client side. If Server, why? & if Client, why? which approach is a best practice. And if you suggest it as Server, there could be possibilities of moving the Server or achieving load balance with different server at that time its not fine to copy all the PDF/Excel. Kindly suggest which technology is preferred and which side is we need to code to download. orelse its better to sent the JSON format to client side technology? Thanks in advance for helping.