UI set Up on different android devices

Hi, I am using unity UI I stuck in the middle I don't know what to do please help me regarding this I created a full game but now when I test on android devices it doesn't appear on full screen please help me regarding this . I do a lot of hard work to make a game but due to this issue, I am struggling please help me? Looking forward to hearing from you. I can send you the project please help me?