How can I get the service speciality?

Thanks for that. AWS has Service Delivery Program to recognize partners who excel in IoT services including Greengrass. Please have a look at this: https://aws.amazon.com/partners/programs/service-delivery/#IoT_Services. For the actual requirements and how to, you will need to use your AWS Partner Central account.

Would like to clarify the ask first? Are you a customer or a partner of AWS? And when you say Service Speciality, do you mean being an expert in the service?