Every ESP will give you tools to create an opt-in form for your site. Generally speaking, the less information you ask for (at this initial stage, at least), the better. The more information you ask for, the less likely your prospect is to complete the process. You’ll obviously need to ask for an email address, and I also highly recommended that you ask for a first name so you can personalize your emails. However, asking for any information beyond these two fields can decrease conversion rates significantly without adding much valuable data.
How do I create a marketing funnel
In marketing automation, Ryan Deiss, co-founder of Digital Marketer, often describes the sales funnel as a multi-step, multi-modality process that moves prospective browsers into buyers. It's multi-stepped because lots must occur between the time that a prospect is aware enough to enter your funnel, to the time when they take action and successfully complete a purchase.