Go to SE61
Go with change option for ZLOGIN_SCREEN_INFO
Document Class: General text
Language: English (OR According to your System)
Name : ZLOGIN_SCREEN_INFO
Note: If you see message that document not found then press create button.
You can also delete existing by pressing delete button and create new. (Create the same ZLOGIN_SCREEN_INFO with class General text and enter the screen info save and activate)
If you want to insert symbols :
Go SE38 > Execute report RSTXICON > Select "icon as abap list" > Execute > it will display list of icons > select the code number from 'code' column > enter this code between two @ symbols.
This will display the icon in login screen page.
Note: If this change as you for transport then Make it LOCAL if you want to use system specific information.