I have CSV file and need to import into Quicken 2016. Which converter should I use?
QFX (Web Connect, not QXF) is the most straightforward choice for Quicken 2016. You cannot set the category (QFX format limitation) and you can import into bank and credit card accounts. You can use Quicken renaming rules to assign the categories. But you cannot do splits (CSV2QFX can do the splits for you by creating separate transactions, which is fine for most case like Paypal payments and fees).
QIF format provides most features comparing to QFX, but requires little bit more work the QFX (Web Connect) format. You can do investment transactions (yes, Quicken 2016 can import "correct" QIF files directly into investment accounts just fine, you just have to follow the instructions and ignore Quicken messages about supported account types). You can do split transactions, you can supply categories and tags. You do have to import through a cash account (call it IMPORT as place to import and then move transactions under correct account). Cash proxy account is required only for bank and credit card transactions, not for investment transactions. Here is full tutorial: