Morphs - yapzhenyie/GadgetsMenu GitHub Wiki
GadgetsMenu does not have built-in Morph feature and is require disguise plugin to enable Morphs.
To enable Morphs, you need to download disguise plugin in your server. Currently, GadgetsMenu only supported Lib’s Disguises plugin and iDisguise plugin for Morphs. Lib's Disguises is a premium plugin and it does support self morph view but iDisguise does not support self morph view.
If you choose to use Lib's Disguises plugin, you need to download ProtocolLib plugin too. If you have downloaded the wrong version of the plugins on your server, you will get errors when using Morphs.