As much as [email protected] seemed suitable to you when you were eleven, chances are things have changed. Keeping an old email or one that is too obscure will almost definitely come across as unprofessional to a prospective employer, so create a new account that is just your name to avoid any embarrassment.
Your email is also an employer's link to finding out more about your social media presence just generally online, so if you like to keep a distinction between those two spheres, it may be a good idea to set up a 'work email' separate from the one you use to sign up on social media with.
Gmail and Outlook are the two most common domain names to use for your email, and for good reason: they're commonly used, and will ensure your cover letter doesn't go to any hiring manager's spam folder. It is common for designers to link their iCloud email accounts, and it may be appropriate to use a university email address when sending out applications as well. Refraining from applying to other jobs using your company account is also always a good idea.
If you're going into entrepreneurship or seriously considering investing in your personal brand, a custom domain can be a way to seem ultra-professional. Still sending out emails from your AOL account? Reference tip one, and restart.
The rookie 'Sent from my iPad' signature can be endearing coming from the CEO of an important company, but won't come off as favourably to a hiring manager who wants to know you've put time and thought into your cover letter.
Double checking your signatures, and making sure you've taken care of formatting (this includes things like font, ninja margins that derail just a single portion of your email, and misplaced header or footer images), will all keep your emails looking both tidy and thoughtful.
Want more advice on applying for jobs? Check out our articles page for tips on everything from cover letters to interviews!