Less is more. User experience ultimately does more for a brand...
This seems counterintuitive but in my experience...the shorter the signature the better the engagement.
I even A/B tested it and found that the larger and more elegant the signature, the less likely it is to get a response.
My hunch is that it creates a formality tension, is less authentic, and in some cases (typically inside sales for an enterprise B2B brand or a recruiter) is the email equivalent of this
Please please please no confidentiality disclaimer! It's useless and toothless. Makes scrolling through a thread on mobile (where 90% of your email will be read and responded to) a real pain. If your legal department demands it, as them to come back and show one court case in history where it was useful. Crickets.
As a side note, I'm involved with a luxury travel business and trade a lot of email with many names you read about and appear on some list on Forbes/Fortune. The kind of folks that can blow $35,000 per person for a 1 week trip for a family of six and not sweat it.
9/10 of them do not use a signature. If they do, it's a mobile number (usually to their assistant). So that's created a bias for me: the bigger and more fanciful the signature, the less relevant you are.
Here's what I've found to be best:
Name. Phone number in a format that mobile devices recognize and are clickable and that the recipient can call AND message you. Label it office or mobile.
Fletcher Christian | +1 (555) 555-5555 mobile
Resist using more than one phone number and make the recipient guess which one is best to use. If you have an office and mobile listed, the user feels like you prefer to not be reached on your mobile. And everyone knows you never actually get someone at their desk. So they don't call. One number is best if you want engagement.
Brain teaser! Can you guess why it's not necessary to include your email address in the signature?
Optional: Company name, title and a website URL if it's not obvious from the company domain name in your email address.
Fletcher Christian, Lieutenant at HMS Bounty | +1 (555) 555-5555 mobile
Resist social links unless you're crushing it on social. Most social links I see on email signatures just highlight how much the brand and/or individual sucks at social. Why would you include a link to your Twitter that you haven't used since August 2014? LinkedIn is perhaps the best assuming a B2B organization and intent is to connect. Think sales or recruiting.
Physical address is ONLY EVER NECESSARY if the intent of most of your email interactions is to result in an appointment or visit at your place of business. Think dentist, restaurant, proctologist, auto repair shop, or tattoo parlor. Otherwise it's useless.
Bottom line: The more email is treated like messaging the better the response and the better for the brand. A brand is ultimately how people feel about interacting with you/your employees/your company.