Hi Debra, I am guessing your question is which should you use. As you create a new profile for a woman that uses her husband's surname, you
1. enter her surname at birth in the Last Name at Birth field
2. enter her current last name or the last name we would look for on her tombstone
3. if she was married more than once or went by other surnames, they should go in the other surname field.
Her WikiTree ID will be created based on her last name at birth, so if you do not know her surname at birth, please use Unknown. Spelling and capitalization counts here, so please use Unknown. I hope this answers your question.