I need help with a software update

I need to download photoshop on my computer, but it says I need to have one of these updates on my computer

• macOS version 11.0 (Big Sur)
• macOS version 10.15 (Catalina)
• macOS version 10.14 (Mojave)

However my computer is only at macOS Version 10.12.6: (Sierra) and it doesn't show any software updates