It is perfectly OK to ignore this alert. A few seconds after the alert appears, the alert should fade away.
However, if you want to pursue this, clicking on this alert should open Software Center. Alternatively, you can open Software Center by selecting the Windows Start icon, typing Software in search, and selecting Software Center. In the top panel of Software Center, selecting Installation Status will display the software that is pending install. If one or more of the records listed displays Requires restart, restarting your PC is indeed required to install the software. As an example, in the below screen shot, there are a few records listed with Requires restart. After restart, these items will appear in Installed Software, and will no longer be listed under Installation Status.