The following applies no matter what that Feature Update's version number might be until and unless Microsoft changes something about the process, and it's been the same since 2015 up until this writing:
First, and most importantly, the best thing you can do is to wait until it's offered to you via Windows Update.
Second, and it really should go without saying at this point in time, every computer user who values their data should be taking full system image backups along with separate user data file backups, and should always take same before ever forcing a Feature Update.
However, I know that many will not follow that advice no matter how often it's been offered and by how many subject matter experts, and in an effort to preclude the, "How do I get it now?," flood I'm going to give the brief "how to" which I hope will stop the flood:
Option 1: Go to the Microsoft Windows 10 Download Page and activate the Update Now button (which triggers the Update Assistant, which will lead you through the Feature Update).
Option 2. On the same page, download the Media Creation Tool via the Download Tool Now button, and use same to create a bootable USB drive to install the Feature Update. Use any one of the following sets of instructions. Doing a Feature Update install takes precisely the same steps, but you're actually doing an update rather than an install-over repair install:
Non-Destructive Repair of Windows 10 - Answers to commonly asked questions
Doing an In-place "Upgrade" to Reinstall Windows 10 Keeping Apps/Programs and User Files
How to: Perform a Repair Upgrade Using the Windows 10 ISO file
Even when I'm doing Feature Updates well after the introduction date on machines that seem to be having issues with Windows Update, I strongly prefer the second option to the first. You already have all the things you need to complete a Feature Update on the bootable media, so even if you experience internet connectivity issues during the update it should still be able to complete.
Still, unless you have very good reason not to do so, the best thing you can do is to wait until it's offered to you via Windows Update.
Addendum: As of this evening the Version 1903 "Health Dashboard" is now active on Microsoft's site. [And this site will probably remain at the same URL for future Feature Updates as well.] It tracks issues that are being encountered (whether fixed or active) during the course of the rollout.
Edited by britechguy, 22 May 2019 - 08:28 AM.
Added notes about taking backups and the Feature Update "Health Dashboard" page.