forms.py

from flask_wtf import Form 
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import DataRequired, Email, Length

class SignupForm(Form):
  first_name = StringField('First name', validators=[DataRequired("Please enter your first name.")])
  last_name = StringField('Last name', validators=[DataRequired("Please enter your last name.")])
  email = StringField('Email', validators=[DataRequired("Please enter your email address."), Email("Please enter a valid email address.")])
  password = PasswordField('Password', validators=[DataRequired("Please enter a password."), Length(min=6, message="Passwords must be 6 characters or more.")])
  submit = SubmitField('Sign up')