You have two options ,
First, To select "All border" from " border" menu. like showing in picture
In case you see this print sheet has a bold borders you can choose the second way which showing in next pictures.
Right click to get this menu (observe that all sheet is selected in this way) to apply your choice on the whole sheet.
Choose "Border " to get this window
Choose the border you like and click around all border cells to liable all the cells, and be ready to print.