The InDesign data merge feature will allow you to create the equivalent of mail merge documents in InDesign. This means that you can create one InDesign document, then have InDesign merge data from an Excel spreadsheet into the document.
So what are the benefits? First of all you don't have to create lots of seperate documents, taking up uneccessary file space. You would also be saving time in that you wouldn't have to type in many details that you most likely have elsewhere.
One thing to bear in mind, is that InDesign merges with csv (Comma Seperated Values) files. So you will need to convert them beforehand. You can use Excel or any spreadsheet for this. When saving the file, ensure that you saving or export the file as csv.
Please check out our Intermediate InDesign Training Course should you wish to learn more.