How many rows can SQL Server process in a single INSERT statement into a table?
According to the documentation the only limitation on the number of rows stored per table is as below


  Limited only by available resources


What local resources does this potentially include?


Memory
Space in the database data files to physically write the inserted data to
Space in the database log files
Space in TempDB (Data and log)


As for how much a single SELECT statement can extract, I cannot find any documentation pertaining to this directly, but I would assume it is safe to take this to be exactly the same as the above.