The majority of the libraries have their own book Indent/requisition form with local fields because of which it is very difficult to make standard online purchase suggestion form within the Library management software. The proprietary ILMS solution may cost a huge amount for the same but open source software gives freedom to customize like Koha. In the current document, I have tried to incorporate some fields for testing purposes which are working fine and other fields can be also added in a similar manner. Please feel free to contact if you need any assistance or suggestions.
Step by Step guide to customization of Koha online purchase suggestion form