I am sure most of us know this, but it may make sense for anyone new to this to read the guidelines that TAXNJ shared. I was at a meeting in 2015 where the presenter announce that the IRS would accept e-signing and then noted that she had been doing it for years (her clients were faxing or emailing her the authorization forms). In actuality, what was happening is that the IRS was allowing a new class of signature with knowledge based authentication when the signature is done remotely using an appropriately secure tool.

On the page TAXNJ linked, they differentiate between in-person and remote signatures, with different rules imposed on the ERO for each type of transaction, but they mention that:
An electronic signature via remote transaction does not include handwritten signatures on Forms 8878 or 8879 sent to the ERO by hand delivery, U.S. mail, private delivery service, fax, email or an Internet website.
I have used a signature pad with my clients for several years which basically requires identity confirmation similar to what I would need to perform if they were signing on a sheet of paper. This is a bit different from CCH eSign which meets the far more stringent requirements for obtaining remote signatures since these signatures are digital signatures rather than digitized versions of handwritten signatures.