There is an enormous amount of Plugins to choose from. To add a Plugin in WordPress you have to select Add New under Plugins menu or next to Plugins tab.
Once “Add New” is selected it will show you a list of popular plugins. Here you can search and browse for Plugins.
Search
Enter the name of a Plugin, select “Search Plugins”, or search by popular tags.
After you have done your way of searching you will see a list of Plugins.
When you see the desired Plugin you can install it by selecting Install Now.
After you have installed the plugin, you can press Activate, or you can Activate / Deactivate plugins at a later time by hovering over a plugin on the Installed Plugins menu and selecting Activate or Deactivate.
Activating a plugin allows you to use it on your site, while Deactivating removes the plugins functionality but allows you to Activate the plugin at a later time.
Upload
This is where you can upload a Plugin .zip file you download from searching the internet. Here is a good site to use when searching for plugins https://wordpress.org/plugins/ or you could Google the Plugin you want.
In the image below you can choose the .zip file to install into WordPress located on your computer and select “Install Now” to install it.
The image shown be will be display telling you the Plugin has been installed and gives you the change to Active it now.
Note: The image above is the same used in Search, this is because you see the same “Installing Plugin” window when the Plugin is being installed into WordPress.