A Research Study to Compare Two Different Versions of Injectable CagriSema in People With Type 2 Diabetes

Inclusion Criteria * Male or female (sex assigned at birth, inclusive of all gender identities). * Age 18-64 years (both inclusive) at the time of signing the informed consent. * Diagnosed with type 2 diabetes mellitus greater than or equal to (\>=) 180 days before screening. * Glycated haemoglobin (HbA1c) 7.0-10.5 percent (%) (53-91 \[millimoles per mole\] mmol/mol) (both inclusive) as determined by the central laboratory at screening. * Stable daily dose \>= 90 days before screening of metformin at effective or maximum tolerated dose as judged by the investigator. * Body mass index (BMI) between 25.0 and 39.9 kilograms per square metre (kg/m\^2) (both inclusive) at screening. BMI will be calculated in the electronic case report form (eCRF) based on height and body weight at screening. Exclusion Criteria: * Renal impairment with estimated Glomerular Filtration Rate (eGFR) \< 30 millilitre per minute per 1.73 square metre (mL/min/1.73 m\^2) as determined by the central laboratory at screening. * Treatment with any anti-diabetic or anti-obesity medication (irrespective of indication) other than stated in the inclusion criteria within 90 days before screening. * Uncontrolled and potentially unstable diabetic retinopathy or maculopathy. Verified by an eye examination performed within 90 days before screening or in the period between screening and randomisation. * Previous exposure to CagriSema in a clinical study.