Hi,
Can you let us know what kind of data you are looking to import.As, you can use excel-addins that are available out of box for certain data imports.
Refer below links:
(Importing Data to AX 2012 Using Excel Add-ins)
community.dynamics.com/.../importing-data-to-ax-2012-using-excel-add-ins
(About importing data from Microsoft Excel [AX 2012])
Importing Data to AX 2012 Using Excel Add-ins
Also, you can use X++ code to import data. It depends on your business requirement, either you can write this code in the clicked method of a button on form (or) as a class method.
Refer below link:
(Import From Excel File Using X++ in AX 2012 - Replace productType table with your table)
axpedia.blogspot.com/.../import-from-excel-file-using-x-in-ax.html
Apart from this, you can use DIXF.
Refer:
blogs.msdn.microsoft.com/.../dixf-importing-data-using-excel-and-odbc