Can't convert disk drive to APFS???

[icy]

I'm trying to upgrade to a latest OS but apparently my mac is up to date already (it's not).
had a look online and apparently I need to convert the drive or something to APFS from mac OS extended journaled.
been into disk utility but the 'convert' tab is greyed out, what am I doing wrong?

 

[Cory Cooper]

Hello and welcome.

A few questions for you:
-Which exact model is your Mac?
-Which version of OS X/macOS is it currently running?
-Is there a specific need to upgrade to macOS Catalina?

The most recent macOS installers will automatically convert the drive to APFS during installation, if the drive is supported.

C