Research Study to Look at How Well Semaglutide Works in People Living With Heart Failure, Obesity and Type 2 Diabetes

This study will look at how participants' daily life is affected by their heart failure. The study will also look at the change in participants' body weight. This study will compare the effect of semaglutide (a new medicine) compared to "dummy" medicine on body weight and heart failure symptoms. Participants will either get semaglutide or "dummy" medicine, which treatment participants get is decided by chance. Participants will need to take 1 injection once a week. The study medicine is injected with a thin needle in a skin fold in the stomach area, thigh or upper arm. During the study participants will have talks with the study staff about healthy lifestyle and physical activity. The study will last for about 59 weeks, that is a little more than 1 year. Participants will have 12 clinic visits with the study doctor. * At 6 of the visits participants will have blood samples taken. * At 5 of the visits participants will be asked to fill in a questionnaire * At 4 of the visits participants will have to do a 6-minute walking test * At 3 of the visits participants will have a test to check the heart. * participants will have their eyes checked before or at the start of the study and at the end of the study Women cannot take part if pregnant, breast-feeding or plan to become pregnant during the study period.