The only what to "know" that the IRS received it is if yiu mailed it certified or registered mail with tracking.
Otherwise,
You can check the status of the amended return here, but allow 3 weeks after mailing.
https://www.irs.gov/filing/wheres-my-amended-return
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**