A plug-in is a software module, which is used with some other applications to enhance the capabilities of that application. Adobe Photoshop
comes with pre-installed plug-ins. These plug-ins perform different type of effects on images.
To use plug-ins in Adobe Photoshop we need to install them in Adobe Photoshop's plug-in directory.When we install any plug-in it will ask you to give the path (some automatically finds Adobe Photoshop). Select the Adobe Photoshop's plug directory. When Adobe Photoshop will run it will automatically read these plug-ins. These plug-ins will be included in the Filter menu.
To use any plug-in, open the image on which we want to use effects. Then go to menu bar and select Filter and then in the end of this menu list select any of the installed plug-in. The plug-in window will open