Here are some ways to merge two PDF files:

1. **Using Adobe Acrobat**:
- Open Acrobat to combine files: Open the Tools tab and select "Combine files."
- Add files: Click "Add Files" and select the files you want to include in your PDF. You can merge PDFs or a mix of PDF documents and other files.
- Arrange and delete content: Click, drag, and drop to reorder files or press "Delete" to remove any content you don't want.
- Save your new PDF: Name and save your file to a location of your choice.

2. **Using PDFBox**:
- Load all the source PDF files you wish to merge.
- Instantiate PDFMergerUtility.
- Add the source PDFs using addSource method.
- Set the destination file using setDestinationFileName method.
- Merge the source PDFs using mergeDocuments method.

3. **Using online tools**:
- Go to http://pdfjoiner.com/ in a web browser.
- Click UPLOAD FILES. It's a teal button in the middle of the page. Doing so will open a File Explorer window in Windows or a Finder window on Mac.
- Select the PDFs you want to combine.
- Click Open.
- Click JOIN FILES.

4. **Using wikiHow**:
- Go to the folder in which your PDFs are stored.
- Select the PDF files that you want to combine.
- Click the Select a file button above or drag and drop files into the drop zone.
- Reorder the files if needed.
- Click Merge files.
- Download the merged PDF.

I hope this helps! Let me know if you have any other questions or if there's anything else I can help you with!