Since version 9.1 and newer, there is a new feature Copy Table has been introduced in SAP Business One which is similar to Copy and Paste function to Excel.
For example, you could copy all items on a SO and paste into a Goods Issue or any marketing document:
Open an existing SO, right click at the table, select Copy Table:
Open Purchase Request and in the item No. field, right click and select Paste:
Click Yes to the prompt:
This is the result:
You could also copy the table into Excel now instead of exporting it to Excel.