Upgrade Drupal 9 to Drupal 10

Step:-

• Install upgrade status modul
• Update all modules & themes
• Uninstall all depreciated module
• Upgrade drupal core to the latest version (min 9.44)
• Backup the code & database
• Make sure upgrade status show 100% 
• Put site to the maintenance mood
• Clear caches
• Change the permission:-
  chmod 777 web/sites/default
  chmod 666 web/sites/default/*settings.php
  chmod 666 web/sites/default/*services.yml
• Swift to admin theme ~ Claro
• Run the update process:-

composer require drupal/core-recommended:^10.0 drupal/core-composer-scaffold:^10.0 drupal/core-project-message:^10.0 --no-update --update-with-all-dependencies

• Run update.php
• If upgrade successfully & have no issue ~ Revert back the permission:-
  chmod 755 web/sites/default
  chmod 644 web/sites/default/*settings.php
  chmod 644 web/sites/default/*services.yml
• Put site to online mood
• Job done !

Resources:-

• https://drupalize.me/tutorial/upgrade-drupal-10