PHP 7.4 reached end of life on 28 Nov 2022 and is no longer being updated. It's strongly recommended to upgrade to the latest version as soon as possible. You can read the official PHP migration guide here.
Installing PHP 7.4 on Server 2019
Prerequisites
Windows Server 2019 installed and updated
Administrative access to the server
Internet connection for downloading PHP
IIS (Internet Information Services) role installed
Installation
Download PHP 7.4 for Windows from the official PHP website
Extract the downloaded ZIP file to a directory (e.g., C:\PHP7.4)
Rename php.ini-production to php.ini
Edit php.ini and set the extension_dir path
Add PHP to the system PATH environment variable
Install the necessary Visual C++ Redistributable packages
Configure IIS to handle PHP requests:
Open IIS Manager
Select the server in the left pane
Double-click "Handler Mappings"
Click "Add Module Mapping" in the right pane
Set the following values:
Request path: *.php
Module: FastCgiModule
Executable: C:\PHP7.4\php-cgi.exe
Name: PHP_via_FastCGI
Click "OK" and "Yes" to create a FastCGI application
Restart the IIS service
Verification
Create a new file named phpinfo.php in the web root directory (usually C:\inetpub\wwwroot) with the following content:
<?php phpinfo(); ?>
Open a web browser and navigate to http://localhost/phpinfo.php
If PHP is installed correctly, you should see the PHP information page