How do you format your crystal reports so that on exporting to word doc or pdf it will not lose the orginal format?

The export option is tricky option. If you are using Word as target use RTF word version makes the report differant. The filed values might be missing if the hight of field is less than height of font. No error is generated in the previous case. The PDF generator is fairly good. 

If provided a choice RPT is the best option for export. RPT will save data with report, user will be able to drill down if needed and user can export to any format if he/she changes mind.
It's best to do few tryals & verify.