how can I update my Safari?

How to upgrade Safari? By updating your macOS. Safari is part of and upgraded with macOS.

Your Mac can be upgraded to at least macOS 10.13, and possibly more recent.

https://www.apple.com/macos/how-to-upgrade/

Apple distinguishes updates—minor changes, and apps are expected to be compatible—from upgrades—larger changes, and can and sometimes does break apps. You’ve probably been checking for updates, but haven’t seen or haven’t considered the macOS upgrades.

For more recent upgrades, your existing apps will need to be 64-bit, or migrated or upgraded or replaced or retired, if your Mac can run Catalina macOS 10.15 or newer. You can find older 32-bit apps using a tool such as the Go64 tool.

Mojave macOS 10.14 is the last version of macOS that can run 32-bit apps.

Microsoft Office 2011 and earlier are all 32-bit apps cannot run on Catalina and newer. You will need Office 2016 (deprecated), Office 2019 (current), Office 2021 (upcoming), an Office 365 subscription, or a migration to LibreOffice (free), or Apple iWork (free) Pages, Numbers, and Keynote can read and write many Office documents.

Have a complete backup prior to the upgrade.

Use only Safari to download the upgrade kit.

If you’d like us to tell you about your upgrade options here, please post your Mac model and Mac model year. See 🍎 > About This Mac for those details. With both the Mac model and the model year, we can tell you your available upgrades.