[TYPO3] Forms in backend

[Sergio Catalá]

Hi, 

I was looking for some extension that allows me to insert certain job
offers on my site but I didn't find anything that suits me. So I thought
about creating my own form in the backend. Is that possible on TYPO3?
Normally when you use a plugin from an extension, there are some fields
you have to fill in the plugin. My interest would be to define these
fields with some extension. 

Thanks in advance, 
Sergio