This trial is conducted in the United States of America (USA). The aim of the trial is to investigate the efficacy, safety, and tolerability of once-daily subcutaneous (SC) injections of NNC0090-2746 for 12 weeks, as an adjunct to metformin, in participants with T2D.

Inclusion Criteria:

• Participants aged 18 to 70 years, inclusive
• Active diagnosis of T2D for greater than or equal to (>/=) 3 months
• For females of childbearing potential and males with female partners of childbearing potential, agreement to use highly effective contraceptive measures
• Treated with a stable dose of metformin for at least 8 weeks prior to randomization, and expected to remain at the same stable dose throughout study participation
• Hemoglobin A1c (HbA1c) >/= 7.2% and less than or equal to (</=) 10.5%
• Fasting plasma glucose (FPG) less than (<) 250 milligrams per deciliter (mg/dL)
• C-peptide greater than (>) 1.5 nanograms per milliliter (ng/mL)
• Body mass index (BMI) >/= 27 kilograms per meter-squared (kg/m^2) and </= 44 kg/m^2
• Stable weight (+/- 5%) within 12 weeks prior to Screening
• Willing and able to maintain existing diet and exercise habits throughout the study
• Capable of performing SC self-injections on a daily basis during the study

Exclusion Criteria:

• Females who are pregnant or lactating
• History of type 1 diabetes (T1D), diabetes resulting from pancreatic injury, or secondary forms of diabetes such as Cushing's Syndrome or acromegaly
• History of acute metabolic complications such as diabetic ketoacidosis or state of hyperosmolar hyperglycemia
• History of clinically significant diabetic complications such as diabetic proliferative retinopathy or severe diabetic neuropathy (requiring treatment with antidepressants or opioids)
• History of severe hypoglycemia within 6 months prior to Screening
• History of chronic gastrointestinal (GI) conditions that could impede gastric emptying or potentially affect the interpretation of the study data
• History of weight loss surgery or weight loss procedure involving the GI tract, such as gastric bypass, gastric stapling, or gastric banding
• History of an eating disorder (e.g., bulimia, anorexia)
• History of malignancy (except treated basal or squamous cell skin cancer) within 5 years prior to Screening
• Personal or family history of medullary thyroid carcinoma
• History of multiple endocrine neoplasia syndrome type 2
• History of chronic or acute pancreatitis or hemochromatosis
• History of significant cardiovascular disease (such as congestive heart failure New York Heart Association Class II to IV, myocardial infarction within the previous 6 months, coronary disease, or uncontrolled hypertension)
• History of clinically significant renal or liver disease
• History of hypersensitivity or previous intolerance to incretin or glucagon analogues
• Elevations in lipase or amylase levels at Screening > 1.5 times the upper limit of normal (ULN) and considered clinically significant by the investigator
• Positive human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAG), or hepatitis C antibody test at Screening
• Receipt of an investigational drug within 30 days or 5 half-lives, whichever is longer, prior to Screening, or active enrollment in another investigational medication or device study
• Any condition, disorder, or abnormal laboratory test findings at screening that, in the judgment of the investigator, would interfere with the participant's ability to comply with all study requirements, or would require the administration of a treatment during the study that could potentially affect the interpretation of the study data, or would place the participant at unacceptable risk by his/her participation in the study