I need to know how to put an accent in Elementary OS I have a QWERTY keyboard in spanish, please help me!
You can try with unicode:
Pressing first Shift+Ctrl+U
Á U+00C1 É U+00C9 Í U+00CD Ó U+00D3 Ú U+00DA á U+00E1 é U+00E9 í U+00ED ó U+00F3 ú U+00FA
There os also another related question that can help you:
I hope it works but haven't tried myself in a password field.