How can I upgrade my Intel(R) Visual Fortran Composer XE 2013 SP1 to Intel Parallel Studio XE 2019 Composer Edition.
Also I need to integrate the fortran 2019 with MSVS 2017.
Can I upgrade 2013 directly to 2019? or I need to buy 2019 ?
If you kept your support license up to date, then yes, you can install the 2019 (or even 2020) version. Otherwise you must buy it again. There are no "upgrades" - every install is the complete product. A current support license allows you to install the latest version, whatever it is. Support renewal is discounted, but if you're more than two years (I think) out it's not available anymore.
If you log in to https://registrationcenter.intel.com/ it will show you the latest version you are eligible to install.