Not sure if this is what your looking for…
public Task UpdateAsync(UserModel model)
{
var user = _dbContext.User.Find(x => x.id == model.id);
user.Password = model.Password;
_dbContext.SaveChanges();
return Task.CompletedTask;
}
It Will get the specific record and Update the password and then save the record.
Edit
Since the password is not getting encrypted i added code to take that string and leave the model as it is, this extension method will encrypt the value of password, i have not test this but i am sure it will work.
user.Password = model.Password.EncryptPassword(EncryptKey);