code that takes inputs for user name amounts etc and then sends custom message

[metulburr]

as sparkz said, you have your code incorrectly indented. The fact that you have all the methods dedented it is not apart of the class, and hence that object does not have those methods at all. Be extra careful with indentation in python...especially when copying/pasting code that it comes out as expected. 

import datetime
 
class MessageUser():
    user_details=[]
    messages=[]
    base_message="""Hi {name}!
    Thank you for the purchase on {date}.
    We hope you are exited about using it. Just as a
    reminder the purchase total was ${total}.
    Have a great one!
     
    Team CFE
    """
     
    def add_user(self, name, amount):
        name=name[0].upper()+name[1:].lower()
        amount="%.2f" %(amount)
        detail={
            "name": name,
            "amount": amount,
        }
        today=datetime.date.today()
        date_text='{today.month}/{today.day}/{today.year}'.format(today=today)
        detail['date']=date_text
        self.user_details.append(detail)
     
    def get_details(self):
        return self.user_details
     
    def make_messages(self):
        if len(self.user_details)>0:
            for detail in self.get_details():
                name=detail["name"]
                amount=["amount"]
                date=detail[date]
                message=self.base_message
                new_msg=unf_mesage.format(
                    name=name,
                    amount=amount,
                    date=date
                )
                self.messages.append(new_msg)
            return self.messages
        return[]
 
obj=MessageUser()
obj.add_user("justin",123.32)
obj.add_user("john",94.32)
print(obj.get_details())