From: zoe1
Most GNU/Linux operating systems come with GnuPG installed on them, so if you're running one of these systems, you don't have to download it. If you're running macOS or Windows, steps to download GnuPG are below. "Before configuring your encryption setup with this guide, though, you'll need a desktop email program installed on your computer. Many GNU/Linux distributions have one installed already, such as Icedove, which may be under the alternate name "Thunderbird." Programs like these are another way to access the same email accounts you can access in a browser (like Gmail), but provide extra features.
+Most GNU/Linux operating systems come with GnuPG installed on them, so if you're running one of these systems, you don't have to download it. If you're running macOS or Windows, steps to download GnuPG are below. Before configuring your encryption setup with this guide, though, you'll need a desktop email program installed on your computer. Many GNU/Linux distributions have one installed already, such as Icedove, which may be under the alternate name "Thunderbird." Programs like these are another way to access the same email accounts you can access in a browser (like Gmail), but provide extra features.
If you already have an email program, you can skip to Step 2.