If u r using classic activities I would recommend to try with SEND HOT KEYS activity and use keys combination like this
Ctrl+end
Ctrl+Pgdn
Or any keyboard shortcut that works there
It will be easy as well
Once after reaching to the end of the page then u can type in value
Or
Directly use type into activity and indicate the files where u want to type but enable simulate type property
That might work in some application
Hope this helps
Cheers @BHUVAN