What you want is to use is the a command instead of the i command to enter insert mode. Or if you want to jump to the end of the line and start insert mode, use A. Note that I will jump to the beginning of the line and enter insert mode.
You can also put
set ve+=onemore into your
.vimrc; that’ll let you put the cursor onto the “empty” space at the end of every line.
Note that $ will still put you on the last character;
you’ll need to use something like $l (lowercase “L”),
99| (vertical bar).