What is the best way to integrate PDF viewing into a website?

Question

CMS

Tell me, the customer previously used Wordpress and had the PDF Embedder plugin installed, which allowed uploading a PDF document to the site and embedding the user's view of this document into any page. That is, you do not need to download the document to view it or open it on a new page. The site was redesigned, without Wordpress and I'm thinking how to make a similar functionality
. I found the following ways:

• Integrate PDF.js - however, it’s useful to deal with it and something seemed to me that everything is somehow very cool there and I will spend a lot of time on this
  
• Use https://docs.google.com/viewer however, as far as I understand, there are restrictions on the size of documents and on the number of views - that is, if the site has a large volume of visits, then this option is not suitable, as I understand it.
  
• Use just the embed tag, possibly wrapped in an object, or an iframe tag - as I understand it - in this case, the document viewing mechanism built into the browser will be used and apparently not all browsers support this feature, but I haven’t found which ones support and which ones don’t and how to add governing bodies
  

I would like to know who uses what and which method is still better and easier.