Which term refers to changing the form or qualities of something?

The term that best refers to changing the form or qualities of something is "modify." To modify means to make partial changes to something, which can involve altering its form, characteristics, or properties to better suit a particular purpose or condition. This term encompasses a range of alterations, from minor adjustments to significant changes, and focuses on the aspect of transformation or customization.

In contrast, "manipulate" often implies a more active handling or control, but doesn't necessarily focus specifically on the form or qualities being altered. "Adapt" involves adjusting to new conditions or environments, which may include modification but is more about a responsive change rather than a direct alteration. "Realise" typically refers to making something real or achieving an understanding, rather than altering its form or qualities. Therefore, the core concept of modifying captures the essence of changing form or qualities most accurately.