How can I create launcher icon for PhpStorm?

Run Tools —> Create Desktop Entry in top menu of IDE.

Use IDE to create launcher. Open Tools -> Create Desktop Entry...

Alternate method:

You need to create a application launcher first.

Installing gnome-panel

 sudo apt-get install --no-install-recommends gnome-panel

To create launcher

sudo gnome-desktop-item-edit /usr/share/applications/ --create-new

This will open up a "Create Launcher" window

Type: Application
Name: PhpStorm
Command: /bin/bash path_to/phpstorm.sh
Comment: Any Comment

This will create a launcher file in /usr/share/applications directory. Now double click and open the file.

Once the file is launched. You can see the process in the unity launcher. Right click on the icon in the unity launcher and click "Lock to Launcher"

Alternatively you can create a .desktop file

Found this .desktop file here. I haven't tested it. Try your luck.

[Desktop Entry]
Version=1.0
Type=Application
Name=JetBrains PhpStorm
Exec=/opt/PhpStorm/bin/phpstorm.sh %f
Icon=/opt/PhpStorm/bin/webide.png
Comment=Develop with pleasure!
Categories=Development;IDE;
Terminal=false
StartupNotify=true
StartupWMClass=jetbrains-phpstorm

Try changing the two below lines in the file ~/.local/share/applications/jetbrains-phpstorm.desktop

Icon=/home/$USER/Downloads/PhpStorm-138.2000.2262/bin/webide.png
Exec="/home/$USER/Downloads/PhpStorm-138.2000.2262/bin/phpstorm.sh" %f