Step 1: Login to the Joomla admin panel.
Step 2: Click on Site on the top menu. Select and click on Global Configuration from the drop-down menu.
Step 3: In the Global Configuration tap, go to the System settings and scroll down. You will see a box called Media Settings.
Step 4: The first item in the box is Legal Extensions (File Types). Next to Legal Extensions, enter the file types you want to allow and separate each with a comma.
Step 5: You can also change the maximum file size, and the paths to the media and image folders here. If you would like to allow any users to be able to upload files, click the No radio button next to Restrict Uploads.
Step 6: Once its completed, apply save changes option to complete the setup.
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