Apple's iMac computers are all-in-one systems. From the exterior, the computer is largely the display. Apple's iMacs offer minimal latitude to adjust the display height. An iMac can be tilted, but the adjustment makes a slight impact on screen height. If you must raise or lower an iMac screen, it may be simpler to adjust the workspace instead. Apple also sells a kit to mount an iMac on a third-party monitor stand.
Adjust the angle of your iMac's display. An iMac display will tilt on a fulcrum. By adjusting the angle, you can slightly adjust the screen height.
Place the iMac on a multi-level desk. If you adjust the height of the surface your iMac rests upon, you will effectively adjust the display height. Look for a desk with a central platform, which can be raised and lowered independent of the work surface.
Purchase and install Apple's Video Electronics Standards Association (VESA) mount. The VESA mount will allow you to attach your iMac to a standard display mount, offering significant height-adjustment potential.
The Apple VESA mount is only available for 24- and 27-inch iMacs.