What is yujis domain expansion?

Yuji Itadori, as of the current story, does not possess a Domain Expansion. Domain Expansion is an advanced jujutsu technique that creates a closed space, imbuing it with the user's innate technique. While Yuji has demonstrated rapid growth and mastery of jujutsu basics, especially thanks to the influence of Sukuna, he has yet to manifest his own unique technique or Domain Expansion. His power primarily stems from his physical prowess, cursed energy control, and application of techniques like Divergent Fist. Whether he will develop a Domain Expansion in the future remains to be seen.