Hi @LohithaSannathi ,
Could you please share a bit more about your scenario?
Do you want to send a approval email after you submit a record using your canvas app?
Further, which data source do you use in your app? SP List data source?
Based on the needs that you mentioned, I think the combination of Power Automate (MS Flow) and PowerApps could achieve your needs. I have made a test on my side, please consider take a try with the following workaround:


embed the App Url Link of your canvas app within the Details field of the "Approval" action along with a ID parameter.
Note: The URL should be enclosed in angle brackets (<>) to meet the Markdown syntax.
Then within your canvas app, set the OnStart property of App to following:
Set(ItemID, Param("ID"));
If(
!IsBlank(ItemID),
Navigate(EditScreen1)
)
within the Edit screen, set the Item property of the Edit form to following:
If(
!IsBlank(ItemID),
LookUp('Your SP List', ID = ItemID),
BrowseGallery1.Selected
)
Please consider take a try with above solution, check if the issue is solved.
Please check and see if the following threads would help in your scenario:
https://powerusers.microsoft.com/t5/General-Discussion/Editing-a-record-from-a-flow-powerapp/m-p/265416
https://powerusers.microsoft.com/t5/Building-Power-Apps/Embedded-link-to-a-Sharepoint-List-item-in-PowerApp/m-p/303910
Best regards,