I just set up the abandoned cart, Do I need to change the email service if I already have webmail service to my website.
ex, 'firstname.lastname@example.org" does this work or I have to join one of the email services mentioned in the instructions?
Thanks in advance
No. It's not true. You can use your 'email@example.com" address (or any address) with Mailchimp or any email processer. Actually, that's exactly what 99.9% of people do. (The 0.01% who don't are just not very bright).
But while deciding what company you're going to use, install the WP-SMPT plugin (If using Woo) or set your mail to SMPT in the Original Plugin's settings. (And use your Web Mail user/password/host)