How can I get a lens profile into Lightroom 6.14 for the Canon 85L 1.4 IS lens?
You can't. That lens was first supported in LR Classic 7.2 / ACR 10.2 in February 2018, two months after the release of LR 6.14. There will be no more updates to LR 6. The only ways to acquire Adobe software that supports the new 85 1.4 is by buying a subscription or by rolling your own.
https://helpx.adobe.com …dobe_Lens_Profile_Creator
Adobe® Lens Profile Creator is a free utility that enables the easy creation of lens profiles for use in the Photoshop family of products, such as Photoshop CC, the Camera Raw plug-in, and Lightroom. A lens profile describes the types of optical aberrations that exist in a particular lens and prescribes how to correct the lens distortions in an image captured from the same lens. For more information, read the user guide (PDF, 1.64 MB). Download: Mac, Win