If you are meaning where are YOUR offsets, in other words you had them in the previous install of Mach but no longer have them then you need to copy over the Tools3.dat from your previous install location. You will find it in the macro folder of the profile you are using. For example if you have it installed in the default location and are using the default Turn profile then it is in C:\Mach3\Macros\Mach3Turn folder.
You can only shorten the first part of the tool call, the first part is the tool number so T0303 is Tool 3 Offset3 as is T303. If you want tool 30 offset 30 then your tool call will be T3030.
Hood