eFiling for minor daughter

[TB121P]

My daughters made income last year they both got 1099 NECs.  I finished their taxes one daughter is 17 the other 15, I can only eFile the Federal for one, the other I can only file by mail. 

What about their signatures on the forms for mailing? Why can't I eFile for my 15 year old?

[DoninGA]

If this is the first time filing for the 15 year old, the tax return has to printed and mailed since she is under the age of 16.