we have the standard table inventsum and there we have qty field which is say i create a new edt type with 3 decimal points and attched to it in edt type
WIll it only get saved in 3 decimal points ot it will display upto 3 decimals points or both???
Both. It rounds any input (though UI) to three decimal places. If you have old data with more decimals or you insert some values through code without rounding, database will contain more decimals but only three will be shown in forms. This is something you should avoid, because it’s confusing and it often leads to additional errors.
You can also invest a minute of your time and simply try it by yourself.