Hi loveideal, welcome to the forum.
You might find your answer in this thread. Please have a look. :)
P.S. Please make make the titles of your posts more specific e.g. What's the difference between 'invitation' and 'offer' or simply invitation vs. offer. This way teachers immediately see what you're looking for and you'll be able to find similar threads at the bottom of this page. Cheers!
Student or Learner