Update: After changing my primary email as a gmail and adding a credit card to the payment methods, Apple finally allowed me to enroll in the developer program. Now I'm waiting for the purchase to be processed.

Thanks Quinn! I am not a member of the apple developer program and this is probably the reason that I cannot use the Wi-Fi Aware capability. When I tried to enroll in the program as an individual, I faced an issue that "Your enrollment in the Apple Developer Program could not be completed at this time". I have contacted the support team but got no response yet. Do you know any common reason of this issue, or is there anything I can try for successful enrollment?

Thanks for your reply Quinn! I'm not a member of the apple developer program. This is probably the reason that I cannot use the Wi-Fi Aware capability as it is not shown in Signing & Capabilities. I have tried to enroll in the program as "individual/sole proprietor" but got prompted that "Your enrollment in the Apple Developer Program could not be completed at this time". I also contacted the support team for this issue but haven't got response yet. Do you know any common reason of it?