Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.
I understand you wish to become Azure express route service provider. @ChaitanyaNaykodi-MSFT have shared an internal alias with you in a private message here. You can reach out to that alias to initiate this process and product group will share the next steps required in this process.
Hope this helps! Please let me know if you have any additional questions. Thank you!
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