Open your HTML email signature file in your web browser.
Press Ctrl / Command + A to select all of the signature, followed by Ctrl / Command + C to copy it.
Login to your Follow Up Boss CRM account. From the top right of your dashboard, click on your Profile icon and name and select My Settings.
In your settings you will see a field below for your email signature. Click inside the field and delete any existing text, then press Ctrl / Command + V to paste your copied HTML email signature.
Click Save at the bottom of your settings and your email signature will then insert when composing emails within your Follow Up Boss account.