Ok normally I wouldn't do this and is not something that I or anyone else on this site usually does, but I made a demo map with a morph ability that allows a high templar unit to morph into an archon for 12 seconds and then detransforms. I leave a temporal link the file of the demo map here: https://ydray.com/get/t/u17162386178339eShFd4b16ad4db0eli
To acomplish this I had to do the following I created 2 custom buffs, then created the morph ability the "morph to" unit to archon in the "Info" field of the ability and then the unit archon needs to turn back as the templar in the "Info Umorph" field of the ability, then created two apply behaviors to manage the duration of the morph ability and handle ability commands, after that I created the issue order commands with similiar parameters as I described in my former post. After that I added two "morph related events" within each unit actor (the actor of the custom templar and the actor of the custom archon), in order to allow the templar and the archon to change its model when it morphs or unmorphs.
So if you want to use this morph ability in another map you need either copy or replicate completely all custom elements of the demo map, which are 2 custom units with 2 added events to each unit's custom actor, a custom morph ability, 2 custom buffs, 4 custom effects. The duration of the "Unmorph Timer" buff, determines the duration of the morph ability. To understand which elements I modified within the custom units, unit's actors, ability, behaviors and effects, check the demo map and check all the data fields highlighted in green in each custom object.
I leave screenshots highlighting the events added to each unit actor and another screenshot displaying where within the morph ability, I added the apply behavior effect, that adds the buff that handles the duration of the morph ability.
Since this took me quite some time, this is my final reply on this subject, if you have doubts about how the morph ability works you can check this entry: https://sc2mapster.fandom.com/wiki/Data/Abilities/Morph, if you need a better understanding of the editor check https://sc2mapster.fandom.com/wiki/ or any of the available online tutorials and forums that dive into the different aspects of the editor.
Best of luck.
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