William Assaf shows how you can use sp_help to learn about temp tables:
For example, I was trying to convert a query from using a #temp table to a CTE instead, and wanted to see the column list and resulting data types of the #temp table.
Sp_help is a helpful SQL Server system sproc to return schema of objects. It’s that magic that happens when you press Alt+F1 in SSMS. (Side note: showing someone the Alt+F1 shortcut in SSMS for the first time and seeing their life change for the better is really rewarding.)
But Alt+F1 doesn’t work on #temp tables[…]
Read on for an alternative which does work.