You can view or download the pdf by either of the two ways i.e by opening it in device in-built browser or in the webview by embedding it in your app.
To open the pdf in browser,
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(pdf_url));
startActivity(browserIntent);
Instead to open in webview,
WebView webView = (WebView) findViewById(R.id.webView1);
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl(pdf_url);