You could use the 'Export Profile' option under the vertical ellipses on your modpack. Make sure you select the needed files for the pack; any custom config, script, or resource files should be checked, along with mods. Then just send them the zip file it creates. They can then click 'create custom profile' and then 'import' and select the zip file you sent. It will set up the pack from there and they can launch it like any other pack.