Thick and Thin Provisioning Differences

I understand it in general but I can't comprehend how it exactly utilizes the space. What I meant. For example, I am having a limitation of 256GB for guest VM hard disk. If I am going to create a new hard disk and will indicate it's size as 256GB (MAXIMUM) and will indicate it's provisioning as THIN then will it expand the size of this hard disk if the content of this hard disk will grow more than 256GB? Please explain it to me. Thanks in advance!