Hi @MAHIMA KANKRIYA ,
You added a document library web part to the sharepoint home page, and then how did you drag and drop the email into the web part? Can you provide me with more detailed steps or screenshots? According to my test, I can't drag the email or its attachment directly into the web part.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.