SQL Server Reporting Services is used for creating, publishing, and managing reports, and delivering reports to end users in various ways, whether that's viewing them in the browser, on cell phones, or as an email in their inbox.
Following are the steps to install SSRS on your existing SQL Server 2014 Express Edition
1) Download the Stand-alone SQL Server Package from Microsoft Website and run it and then click on New SQL Server stand-alone installation or add features to an existing installation.
2) Select add features to an existing instance of SQL Server and click Next.
3) Tick the Reporting services -Native in feature selection and click on the Next.
4) Keep the startup type automatic and click on Next. Here, you can set the Password for the SSRS account.
5) Keep the startup type automatic and click on Next. Here, you can set the Password for the SSRS account.
That's it. Reporting service feature installed successfully.
You can also refer to the following URL for more info. https://manage.accuwebhosting.com/kn...s-Edition.html