To install PHP 8.3 on Fedora 40, you can follow these steps.
Step 1 : First, ensure your system is up-to-date by running:

Step 2 : Add Remi's repository to your system by executing:

Step 3 : Check available PHP modules using:

Step 4 : Enable the PHP Remi repository:

Step 5 : Install PHP core along with PHP-FPM and CLI:

Step 6 : Install commonly used PHP Extensions. You can select extensions based on your requirements:
Explanation:
mysqlnd: MySQL native driver.curl: Client URL Library.gd: GD Graphics Library.mcrypt: Encryption algorithms.json: JavaScript Object Notation support.pear: PHP Extension and Application Repository.common: Common files for PHP.xml: Extensible Markup Language support.zip: ZIP archive support.devel: Development files.xsl: XSLT extension.soap: Simple Object Access Protocol extension.bcmath: Arbitrary precision mathematics.mbstring: Multibyte string extension.gettext: Gettext support.imagick: ImageMagick PHP extension.

Step 7 : Verify the PHP version installed:

Congratulations! You have successfully installed PHP 8.3 on Fedora 40.