Important Note Before You Begin:

Apple no longer officially distributes El Capitan through the normal "Purchased" tab in the App Store for most accounts. However, Apple still hosts the installer on its software update servers. The official, safest way to get it is using a direct curl command or a link from Apple's support site (not a random third-party download, which may be malicious).

Compatible Macs generally include models from 2007 to 2015, such as iMac (Mid 2007+), MacBook Pro (Mid/Late 2007+), and MacBook Air (Late 2008+). Restrictions:

For older hardware that cannot run modern browsers, you may need to use a browser like Firefox ESR to successfully initiate the download from Apple's servers. create a bootable USB installer using the Terminal once you have downloaded the app? How to download and install macOS - Apple Support

The Terminal Command:

You will need a USB drive named "MyVolume" (at least 8GB) and the installer app located in your Applications folder. Open Terminal and paste:

3. Press Enter. The 6 GB file will download to your Downloads folder as InstallMacOSX.dmg.
4. Wait for completion (can take 20–60 minutes depending on internet speed).