Hi hems,
If you mean that Excel is changing numbers entered without
a decimal point to something else like changing 123
to 1.23 or .0123 or 12300 then that would be the
fixed decimal input feature most useful to accountants.
Tools, Options, Edit (Tab), remove checkmark by Fixed Decimals
There are two items when you use Format, Cells, Number
one is thousands separator, and the other is the number
of decimal places.