Hi Ramandeep,
Thanks for posting in the community.
Based on your query, you want to merge your pdf files in SharePoint.
As of now, you can only merge PDF files directly in SharePoint Online using the built-in functionality provided by Microsoft Syntex or SharePoint Premium, without needing to download them.
Here is what you have to ensure before doing so.
- You must have a Microsoft Syntex license or SharePoint Premium features enabled.
- The PDFs should be stored in a SharePoint document library or OneDrive.
Here is the merging steps once you have the license:
- Open a PDF in your SharePoint document library.
- Click on the More options (⋯) at the top left of the screen.
- Select Merge.
- Choose the other PDF files you want to combine.
- Click Next, then choose where to save the merged PDF file.
- Confirm and the new merged PDF will be created in your selected location.
Refer to: Merge and extract PDF files in SharePoint - Microsoft Syntex | Microsoft Learn
If you don’t see the “Merge” option, your organization might not have Syntex or SharePoint Premium enabled. You can check with your IT admin to confirm. If you don't have the license to do so, it's best to use other online tools if allowed by your IT policy or Adobe Acrobat to merge them.
Should you have any questions related to this topic, please don't hesitate to reach out.
Sincerely
Alexis-NG | Microsoft Community Support Specialist