If you have an active Microsoft 365 subscription, you are entitled to download older versions of the software through the App Store or Microsoft’s website.
: This is the last fully compatible version for El Capitan. While newer versions like Office 2019 or Microsoft 365 require macOS 10.12 (Sierra) or later, you can still install and run Office 2016. Microsoft Office For Mac Os X 10.11 6 Free Download
If you're looking for a free download, you can try the following options: If you have an active Microsoft 365 subscription,