Q. How can ask to reserve a book with large print when it has no defining in cataloge!

To search for items that are in large print, you have two different options. You can either use the advanced search to select the format "large print" specifically, or for items that result from a regular search, on the left hand side there is a limiter labeled "Large Print" under "Format." If you select this, it will limit the returned items by which are only available in large print.  If this limiter is not available then the library may not have large print options.