Why my app rejected?
It might be because your App is “too simple”. Have a look at the other iOS Items and see how they’ve done it. Just ask yourself, does your App provide any features that people / developer need or are looking for? Would you buy it yourself as it is? Go over the features of your App again and try to build a nice User Interface, write a good documentation on how to use your App, create your App Description (A bit more than one line) and make nice preview pictures. Just my thoughts on that as i had a little struggle myself in the beginning
If i add touch id login and change design. It will be better?
Well, that’s not exactly what i meant. It will certainly help. But just have a look at these 3 Items that offer the same as you:
You should now ask yourself “What has my Item, that these Items don’t have”.
The Idea is to provide unique features, or a unique combination of features.
You should always check what already exist and if it already exist that you want to provide, how can you make it in a way that makes your item stands out from the rest.
I hope this helps a little bit in getting the idea.