Thanks!! Signature has been sorted, thank you!

Keiron B. Hi again! We will add this request to the list of changes for the future Signatures related project. The good news is that technically it will be possible to use Helvetica font, as it is already supported in our recently revamped Templates editor. However, we want to be transparent in setting expectations - consistent rendering across all devices remains outside of our control. Unfortunately, this limitation still applies.

As also mentioned during our call, you can use Mailbutler Signature on mobile, the workaround stays the same:

Please be aware that Apple allows to use only text https://support.apple.com/en-gb/guide/iphone/iph80dabb18b/iosformat