Apple does not provide any external or online "link" to check an SEID. The only way to view your SEID is directly on your device. The phrase "SEID iPhone check link" is likely a misinterpretation of the process, which is:
The original query "seid iphone check link" points to a common point of confusion in digital security: mixing up internal hardware identifiers with external threat detection. While the SEID is a critical part of your iPhone's security architecture for payments, it is a tool for checking links. seid iphone check link
If you cannot access the iPhone's screen, you can check identifiers through your Apple Account: How to Find the SEID Number on iPhone 16 Pro! Apple does not provide any external or online