You can use the below code to delete the file from document directory:
NSError *error;
NSFileManager *fileMgr = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *documents= [documentsDirectory stringByAppendingPathComponent:@"YourFolder"];
NSString *filePath = [documents stringByAppendingPathComponent:@"file2.txt"];
[fileMgr removeItemAtPath:filePath error:&error]