Create a quiz form that will show the total score on the Thank-You page

How do I create a quiz where all the questions are on the same page and the answers show up after someone submits their answer?  Or is the only way a quiz can be done with answers is if there is one question shown at a time?

How do I create a quiz where all the questions are on the same page and the answers show up after someone submits their answer?

You can turn your form into a quiz form by following the instructions in this guide — Turn-your-form-into-a-Quiz-or-Exam-

However, if you want to manually make your form into a quiz form, that would also be possible.

You just have to set the correct answer in a question (Single Choice field) using Calculation Values.

Then, use a Form Calculation widget to total the answers or get the percentage of the total correct answers.

You can also show a different Thank-You page based on the total score.

Change-Thank-You-Page-URL-Based-on-a-Condition

Here's a Sample Quiz Form — https://form.jotform.com/82065569135966

On that quiz form, you'll get a different Thank-You page if your score is 60% and above.

Or is the only way a quiz can be done with answers is if there is one question shown at a time?

No, making your form into a quiz form also works with the "ALL QUESTIONS IN ONE PAGE" layout (classic layout) and not just with JotForm Cards.