Every time I open Ai I have to press CTRL+R to show ruler , i need to keep it always.
Did you turn on in Preferences > Show/Hide Rulers?
No, I can't reach it in preferences !
I found it in view menu just show or hide.
thank you I found it in (general) preferences
Good to hear you found it.
Once it is turned on you will see rulers in new documents when they are turned on in your current document.
If you turn rulers off, all your new document will have rulers off.