SignPadding

SignPadding
is an option for NumberForm and related functions that specifies whether padding should be inserted after signs.

SignPadding->True specifies that any padding that is needed should be inserted between the sign and the digits in a number.

SignPadding->False specifies that the padding should be inserted before the sign.

The default pads before signs:

Pad between signs and numbers instead:

The default pads before signs:

Out[1]//NumberForm=

Pad between signs and numbers instead:

Out[1]//NumberForm=