why does my logo not appear

I can see that you have already added a logo using the Image element on your form.

I have cloned your form and I was also able to add an image to the Logo placeholder of the form.
Cloned Form URL: https://form.jotform.com/81036406114950

If you are having any problem, I suggest you try clearing the cache of your browser and the cache of your forms.

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Clear your web browser's cache, cookies, and history
How to Clear Your Form Cache?

Let us know if you need further assistance.