Firstly they need to know where it happened. To get that information we use the context status. This  information about the transaction and even field can be displayed by right-clicking the mouse and selecting Show context ID.  The important info to share is the TRN(which transaction you were in) and maybe the field if that is relevant. 

Place the cursor on the field>Right Click>Select Show context in Status line

Now when you report the bug you can say I was in transaction xyz and field abc has this thing wrong with it . 

Good practice for reporting bugs :

1. State what you did (Steps to reproduce)
2. State what happened (the bad outcome ) 
3. State what should have happened (this will be used by the developers to check if they fixed it) 
4. A picture tells a thousand words - Screen shots,  exact error message text , video all really help.