In Angular forms (both ReactiveForms and Template-driven forms), setValue and patchValue are used to update the values of a FormGroup, FormArray, or FormControl. However, they behave slightly differently in terms of how strictly they enforce the structure of the form's controls. setValue requires that the object you pass must match the structure and contain all the keys of the controls in the form. If a key is missing or if you provide extra values that don’t exist in the form structure, it will throw an error. patchValue allows you to update only some of the controls in the form. You can pass an object with a subset of the form's controls, and only those controls will be updated. The rest of the form remains unchanged. It also ignores extra keys that don’t exist in the form without throwing an error.