can I upgrade directly from High Sierra to Catalina on my mac

Yes, if your Mac is compatible with it.

(176303)

If your Mac is compatible with Catalina, yes.

Make absolutely sure that you do not have any 32 bit applications that are critical to you as they will not run on Catalina.

Also, as always, make doubly sure that you have at least one, preferably two good backups before attempting to upgrade.