I have a requirement where I want to merge two pdf into a single pdf and attach the attachments to the custom object in Salesforce.

PageReference pdf = PageReference(/apex/FirstPDF?id='+ccId);
Blob contentPdf = pdf.getContent();
PageReference cadre = new PageReference('/apex/SecondPDF?id=' + ccId);
Blob b = cadre.getContentPdf(); String combinedPdf = EncodingUtil.convertToHex(contentPdf)+EncodingUtil.convertToHex(b);
Blob horodatagePdf = EncodingUtil.convertFromHex(combinedPdf);
Attachment attachment = new Attachment();
attachment.Body = horodatagePdf;
attachment.Name = String.valueOf('New pdf.pdf');
attachment.ParentId = ccId; insert attachment;