Yes, however the NFC function within the iPhone 6 can only be used for making payments. The iPhone 6 cannot be used for scanning NFC tags, even with an App.
With the recent release of iOS13, Apple added a host of additional functionality to the iPhones that can read NFC tags, which include the iPhone 7, 8, X, Xs and Xr. However, no NFC support was added to the iPhone 6 and it's fairly safe to say at this point that the iPhone 6 will never be able to read NFC tags either with or without an App.
No. As with reading NFC tags, this situation is not likely to change.
The table below illustrates the available NFC tags and their compatibility with your phone. As phone specifications can change without notice and also vary from region to region, we strongly advise testing tags before any purchase.
|MIFARE Ultralight® EV1||No|
Depending on what information you need to store on your NFC tags, you will have different memory requirements. NFC Tags have a very limited memory so getting a tag that will store everything you need is important. Seritag have put together some information on how much memory you will need in your NFC Tag.