I think the link given by Sahil is for Exporting PHOTOS with a Preset.
Preset files (.XMP) are basically 'text' files that work in both PC and Mac. And there is no 'Export' function in Lightroom-Classic for the Presets.
The way I "share" is to simply copy the .XMP files (and previously the 'old' .LRTEMPLATE) with a file browser and paste them to another computer. I also save a copy of the folders as a backup in my Creative Cloud folder, where they are available wherever I might want.
This article will tell -where you will find your preset files:
OK - this is what I'm having trouble with. "copy the files with a file browser and paste them to another computer." I don't know what file browser is, and I don't want to paste them to another computer, even if i knew how. I want to be able to send the files between both MACs and PC and share with anyone. I don't want to sync settings, I want to share the presets i've created with other lightroom users
Both .XMP and .LRTEMPLATE preset files can be considered as 'text' files, and like most text, word, files they can be copied to any folder, USB stick, another drive, another computer. It is done in the operating system Mac/Finder or Windows/File Explorer (File browsers!). So copy the files, compress them in a .ZIP file if you want, then send, share, or save them as backups.