I am using Adobe Acrobat DC and I find that I am often making the same formatting changes to things like date fields so that they appear dd/mm/yy or turing off border and fill colours for tick boxes/radio buttons.
Is there a way to set these defaults at a program level, so that I don't need to keep making these small changes?
For border and fill colors, right click on field and at the bottom click on ' Use current properties as new default'.
You can't set the default Date format used, but you can apply the same format to multiple fields in your file (after they were created), using a script.
For example, this (paid-for) tool I've developed allows you to do just that in a few clicks: https://www.try67.com/tool/acrobat-apply-format-to-multiple-text-fields