Customise Touch Bar for a specific application
Assuming I understand your question, you can set your Touch Bar to show the function keys as its default display on an app by app basis.

To do this:


Go to Apple > System Preferences
Select the Keyboard preference pane
Click on the Shortcuts tab
In the left sidebar, select the Function Keys option
On the right-hand side click on the plus + button
Select the JetBrains PhpStorm app
Add the app


Now, whenever you are using the JetBrains PhpStorm app, the Touch Bar should display all the function keys.