This answer is for if you are using AS2
Make an input text field (give it a label, like inputName), and below that a button.
then place this code on the button
on (release) {
if(inputName == "What you want them to type in") {
gotoAndStop(frame number);
}
}
they have to match it with capitalization with this method.
you can use the toLowerCase() function on their input to make it so that capitalization does not matter.