email question

i don't use your dns service, but i want to use your email service ,so how should i do?

Create email accounts in our hosting account panel. Then copy our MX and TXT records from our DNS zone to your DNS provider's zone.

one more question, when i send an email,it is fast .But when i test to receive an email from qq.com, outlook.com,it will be so slowly.Why is that?

We have tested (outlook.com) and we don't see such an issue. We also do not use greylisting.