PDF Merge Tool is a simple, fast and easy tool for merging PDF files. Here is the link to the PDF Merge Tool.
Also : Checkout PDFill PDF Tools, free desktop utility program which lets you to split any pdf file into smaller pdf files or lets you to combine PDF files into a single document with more flexibility and control.
Do you know how to split pdf file into many parts ? or how to merge multiple pdf files into one big file ? If not then consider PDFill PDF Tools, This is a free desktop utility program which lets you to split any pdf file into smaller pdf files or lets you to combine PDF files into a single document with more flexibility and control.