>I used a report designer to creae a invoice report.
>How can i start the page no. from 1 in different invoice no.

If you create a Data grouping based on the Invoice number you can control this. Click Report/Data grouping and create the grouping you want, checking off "Start Each Group on a new Page" and "Reset Page Number to 1 for Each group".

>And I also want to know how to set the line per page in the invoice.frx

Assuming you dont have any stretching memo fields, it's just a matter of how many records fit on a page give thet height of the various bands. You can control when it will try and start a group on a new page if it's closer than the distance you specify under "Report/Data grouping".