They offer email addresses through Google Workspace. This is a professional solution but it will set you back $70 per user (yearly). For many, this won’t be ideal as it’s a bit pricey.
A better approach would be to purchase your domain name through an external registrar, (e.g. Namecheap, which is the cheapest option we know of), point it to Weebly and set up email there. Namecheap charges around $10-15 per year for a domain name and another $10 per email account.
Find more information in this guide on Weebly email addresses and domain names.