Passing blocks in Objective-C

When writing a method that accepts a block as an argument, do I need to do anything special such as copying the block to the heap before executing it? For example, if I had the following method:

- (void)testWithBlock:(void (^)(NSString *))block {
    NSString *testString = @"Test";
    block(testString);
}

Should I do anything with block before calling it, or when entering the method? Or is the above the correct way of using the passed-in block? Also, is the following way of calling the method correct, or should I do something with the block before passing it?

[object testWithBlock:^(NSString *test){
    NSLog(@"[%@]", test);
}];

Where do I need to copy the block? And how would this have been different if I wasn't using ARC?