Where to store constant strings

In my app i have about 30 strings i would like to store somewhere. I want to use it in couple classes later, and it will be used only once in every class. Where is the best place to store it? I read about singleton class in ios, but i'm not sure if this is solution for me.

I want to make something like NSArray where in for loop i can search the array.

I've tried to define it like:

NSArray *arr = [NSArray arrayWithObjects:@"something",@"else", nil];

But i can do it in .h file, and i'm not sure if for constant variables i want to have a class.