You need to use an exploded WAR which is an unpacked WAR and its directory structure into JBOSS_HOME/server/default/deploy; or wherever is appropriate for your run-time instance. You can then just copy the required file into the WAR subdirectory under deploy.
Is this the easy way? Is very hard to save the pdf (And Link it) out of the " default/deploy/web-client" directory?
Yes it is the easiest way if you want the file to be available as a standard static file. You will need to call the subdirectory under deploy web-client.war so you can access the static content as http://localhost:8080/web-client.
As I see, the index-button does a submit..
If this submit is to a servlet, which I assume, since you otherwise would have just named the jsp that generate the PDF ; index.jsp...
Well. In index.jsp you can directly load the content of a servlet by letting the index.jsp contain only one line :
<jsp:include page="/YourServlet" flush="true"/>
If you want want a link on index.jsp instead, yoy create the form as usual, omit the submit-button, and creates a link like link-text