I take it you want to record in FTM a child of a woman other than a man who she was married to. A hundred years ago, this child was called illegitimate. I doubt if anyone these days would use that word to describe that child.
Anyways, let's start with fixing what you've got and then look at how to record these children in the future.
Select the child.
Go to Main Menu > Persons > Attach / Detach
You will see all of the family relationships that child is a part of.
Select the one that shows her as a daughter of Eliza Smith and John Jones.
Clck ok.
She will still be selected in the family or person page, but now without any parents.
Go back to Menu > Persons > Attach / Detach / Attach Mother
You will see Eliza Smith listed twice, once as the wife of John Jones and once as wife of "No Spouse Entered". Choose Eliza and "No Spouse Entered".
Click ok.
_________________________
In the future, either
1) add the child from the unmarried mother before adding the husband or
2) actually give a name to the father "unknown", or Mr. Jones or whatever.
3) Add the child as an unrelated person (Menu - Persons - Add Unrelated person). Then, add her as a child as above.
Anyways, let's start with fixing what you've got and then look at how to record these children in the future.
Select the child.
Go to Main Menu > Persons > Attach / Detach
You will see all of the family relationships that child is a part of.
Select the one that shows her as a daughter of Eliza Smith and John Jones.
Clck ok.
She will still be selected in the family or person page, but now without any parents.
Go back to Menu > Persons > Attach / Detach / Attach Mother
You will see Eliza Smith listed twice, once as the wife of John Jones and once as wife of "No Spouse Entered". Choose Eliza and "No Spouse Entered".
Click ok.
_________________________
In the future, either
1) add the child from the unmarried mother before adding the husband or
2) actually give a name to the father "unknown", or Mr. Jones or whatever.
3) Add the child as an unrelated person (Menu - Persons - Add Unrelated person). Then, add her as a child as above.