This is where you need to research well for the same. Dig deep, find out the most applicable requirements, and then choose a company that satisfies those requirements. Additionally, you should look for a company with references you can talk to. Usually, a company must have-
1. More than 5 years of experience in developing cross-platform apps
2. A team with expertise and experience in the very field
3. Agile methodology throughout the app development process
4. Post-development assistance on all the delivered projects, and so on.
To get world-class Cross-Platform App Development Services, you need to explore these qualities to have your projects delivered with no hassle.