Yes!! If your app is configured for secured access - i.e. users are authenticated by login - then AppSheet provides a USEREMAIL() function allowing you to retrieve the logged in users email address.
The app can use this value to automatically lookup the Name from your internal app table.
after two days i found the solution (using LOOKUP):
i searched with keyword “lookup the Name from your internal app table appsheet” as suggested by @WillowMobileSys and google AI gave the result:
LOOKUP(value, dataset, column, return-column)
Example:
If you want to get the “Name” from the “Customers” table for the customer whose “Email” is the same as the current row’s email, the expression would be: LOOKUP([_THISROW].[Email], "Customers", "Email", "Name")
I apologize! It didn’t really register with me that you were looking for specific lookup functionality on how to do it. I would have given more details.