It’s possible to use symbols in your emails, it can be a fun thing to add to your communication.
But, this should be used with caution! Symbols in subject lines are not supported in in all email clients. Not all symbols are universally supported either, so make testing an important step in your decision.
Also remember that subject lines are not HTML code so you can't use entities as you would have in the actual email content. You need to copy the symbol from a website or document and paste it into subject line field.
Here is a website you can try with: fsymbols.com. Also remember to have your email project/folder encoded with UTF-8 to make this work. This is set under account + project admin.
Keep in mind that if a character isn’t supported in the email client, the recipient will see a ☐ character instead or the word ‘emoji’. Your symbol may also be substituted to another symbol. In our own tests, symbols does not automatically end up in spam folders, but there are indications of some email clients being sensitive to those kind of subject lines. So, test, test and test!
Below is a sheet of current client support:
*Emoji is a special set of images and emoticons