model 21 is not a complete model number, sorry.
the service tag tells you that. look find it and write that down
or run Hwinofo32.exe free, and see if VT(x) is there.
turn It on in bios. (no 2 bios the same ,means YOU LOOK)
some processors have others not,.
unless you know your processor real model number , there is no flat answer possible.
other than the program listed above.
best I CAN tell counting 105 AIO PCs ,you have a
the PAVILION not stated. name.
guessing I am, you model is not fully stated
hp all in onemodel 21
HP Pavilion 21-a000 All-in-One Desktop PC seriesTHIS IT?
your page is herehttps://support.hp.com/us-en/drivers/selfservice/hp-pavilion-21-a000-all-in-one-desktop-pc-series/5287669
lots of sub models, and processors fitted
one is G3220T intel.
so when you learn that number
go to wiki below and see if Vt(x) is a features.
or here and shows limited support
in the run box type system information
then see what processor you have.
then look here.
if PC is modern it has CORE(tm) intel processor
go there and see if VT(x) is supported, many are not. for sure the cheapest processors.