Login in to your Mail Chimp account
Step 1: Create an audience (for e.g. Create Subscriber for Tejash.me)
Step 2: Create a signup form
Step 3: Embedded forms (Copy ACTION URL from FORM Replace it URL: “https://xxxxxxxxx.list-manage.com/subscribe/post?u=xxxxxxxxx&id=xxxxxxx”, in below code

Shopify please create a snippet newsletter.liquid
{{ newsletter_form }}