When searching for a free download, you will likely encounter sites offering a standalone setup.exe or "highly compressed" versions. You should approach these with extreme caution for several reasons:

Pirated or unofficial versions cannot connect to EA servers, meaning you lose access to Ultimate Team and online seasons. How to Install FIFA 16 Correctly

Before downloading any large files, verify that your PC can handle the game: Windows 7/8/8.1/10 (64-bit)