In Ultima 8, the debug mode exists but not accessable without some 
DEBUGing or using external programs that debug for you.  Here's how:

Using a text editor create a file called avatar.deb in the
\ULTIMA8\GAMEDAT directory with the following text:

E 12A
01 01
W
Q

then save the file and at the DOS prompt type:

CD \ULTIMA8\GAMEDAT
DEBUG AVATAR.DAT < AVATAR.DEB

Run U8 and immediately save your game.  Use F7 and CTRL-F1 to enter
cheat commands.