Hello Anastasia
If you want any clicks coming from people accessing the email from social media, etc, then you can open your email in your browser using the "view in browser" link, then use the url for the resulting page. In this case, however, any interactions coming from those sources will be attributed to you or to whichever person the email you obtained the mailto link from was sent.
If you don't want those interactions tracked, you can copy all of the content from your email template, pasted it into a landing page, and then link to the landing page.