How do I add my email signature to AirMail for Mac?

Open your signature on htmlsig.com in Chrome or Firefox (avoid Safari, which can cause layout issues).

Select your signature and copy it to your clipboard (Cmd + C).

Open AirMail, then from the menu bar select Airmail 3 > Preferences.

On the Accounts tab, click the settings (gear) icon next to your email account.

Select the Signature tab, choose your account, and click the + icon to create a new signature.

Name your signature, then click into the text box and paste your copied signature (Cmd + V).

Click Save.