How to add static(html, css, js, etc) files in pyinstaller to create standalone exe file?

From your question you can presume that the structure of your project is as follows:

├── index.html
├── jquery.js
├── main.py
├── my_custom.js
└── styles.css

For your case there are 2 options:

1. using --add-data

   import os
   import sys
   
   from PyQt5 import QtCore, QtWidgets, QtWebEngineWidgets
   
   
   def resource_path(relative_path):
       """ Get absolute path to resource, works for dev and for PyInstaller """
       try:
           # PyInstaller creates a temp folder and stores path in _MEIPASS
           base_path = sys._MEIPASS
       except Exception:
           base_path = os.path.abspath(".")
   
       return os.path.join(base_path, relative_path)
   
   
   if __name__ == "__main__":
       import sys
   
       app = QtWidgets.QApplication(sys.argv)
       view = QtWebEngineWidgets.QWebEngineView()
   
       filename = resource_path("index.html")
       url = QtCore.QUrl.fromLocalFile(filename)
   
       view.load(url)
       view.show()
       sys.exit(app.exec_())
   

   If you want to add external resources to the executable then you must use the “–add-data” option:

   pyinstaller --onefile --windowed --add-data="index.html:." --add-data="jquery.js:." --add-data="my_custom.js:." --add-data="styles.css:." main.py
   

   For windows change “:” with “;”.

2. using .qrc

   With this method you will convert the files (.html, .css, .js, etc) into .py code using pyrcc5 for this you must follow the following steps:

   2.1. Create a file called resource.qrc with the following content in the project folder:

   <RCC>
       <qresource prefix="https://stackoverflow.com/">
           <file>index.html</file>
           <file>jquery.js</file>
           <file>my_custom.js</file>
           <file>styles.css</file>
       </qresource>
   </RCC>
   

   2.2 Convert it to .py using pyrcc5:

   pyrcc5 resource.qrc -o resource_rc.py
   

   2.3 Import the resource_rc.py file and use the url with schema “qrc” in the main.py file:

   import os
   import sys
   
   from PyQt5 import QtCore, QtWidgets, QtWebEngineWidgets
   
   import resource_rc
   
   
   if __name__ == "__main__":
       import sys
   
       app = QtWidgets.QApplication(sys.argv)
       view = QtWebEngineWidgets.QWebEngineView()
   
       url = QtCore.QUrl("qrc:/index.html")
   
       view.load(url)
       view.show()
       sys.exit(app.exec_())
   

   2.4 Compile the project using your initial command

   pyinstaller --onefile --windowed main.py