Import will automatically import most common file formats as a suitable expression :

Import["ExampleData/cities.xlsx"]

If Importcannot determine the format of a file, you can specify it explicity:

Import["ExampleData/cities.xlsx","XLSX"]

Import["ExampleData/cities.xlsx","Dataset"]

Import["ExampleData/cities.xlsx","Elements"]

Specify which element to import:

Import["ExampleData/cities.xlsx","Images"]