First you need to make the command!
Then:
cmd create vanish
Then:
cmd add vanish load %vanish%
cmd add vanish if varset(%vanish%[%p%]) = 0 then let %vanish%[%p%] = \"off\"
cmd add vanish let %checkvanish% = %vanish%[%p%]
cmd add vanish if %checkvanish% = \"off\" then goto 7
cmd add vanish if %checkvanish% = \"on\" then goto 12
cmd add vanish exit
cmd add vanish ascon /effect %p% invisibility 10000 1 True
cmd add vanish message %p% [Vanish] You're vanished now!
cmd add vanish let %vanish%[%p%] = \"on\"
cmd add vanish save %vanish%
cmd add vanish exit
cmd add vanish ascon /effect %p% invisibility 0 0 True
cmd add vanish message %p% [Vanish] You're no longer vanished!
cmd add vanish let %vanish%[%p%] = \"off\"
cmd add vanish save %vanish%
cmd add vanish exit