https://docs.magento.com/m2/ce/user_guide/cms/editor-insert-variable.html

Your store includes many predefined variables that can be incorporated into content pages and other communications. In addition, you can include your own custom variables that are specific to your needs.

コンテンツに組み込み可能な定義済みの変数を含められます。加えて、必要に応じて定義するカスタム変数を含めることもできます。

To insert a variable on a page:

1. Do one of the following:
  • Open an existing page.
  • Create a new page.
2. In the panel on the left, choose Content. Then from the editor, do one of the following:
  • Position the cursor where you want the variable to appear, and tap Insert Variable.
  • If you prefer to work with the code, click Show / Hide Editor. Position the insertion point in the text where you want the variable to appear. Then, tap Insert Variable.
3. In the list of available variables, choose the one you want to insert into the page.
4. When complete, tap Save.