MailChimp is one of the most popular email list management services available right now. If you are using this service in your WordPress website, then you need to use the MailChimp for WordPress plugin too. This absolutely free plugin offers simple and easy solutions to connect MailChimp with your website and build your subscriber list.
Getting Started
First of all, download and install MailChimp for WordPress from the WordPress plugin repository. Once you activate the plugin, it will create a new menu item titled ‘MailChimp for WP’ in your website dashboard.
Connecting your MailChimp Account
Go to MailChimp for WP > MailChimp to start the setup process.

As you can see, you will need an API key to connect the plugin with your MailChimp account. To do that, click the ‘Get your API key here’ link. In the resulting page, you will be asked to log in to your MailChimp account.
Once you are logged in, you will be automatically redirected to the API page. Find the ‘Your API keys’ section and copy your API Key.

Next, get back to the plugin’s setup page. Provide the API Key and click ‘Save Changes’. If everything is okay, your website will be connected with your MailChimp account and a green ‘CONNECTED’ sign will be displayed.
The plugin will also import your existing lists and display them in the ‘MailChimp Data’ section.

Including Checkboxes in Forms
Now that you have MailChimp connected with your site, let’s see how you can include optin checkboxes into various places of your website. To do that, go to MailChimp for WP > Checkboxes. You will be taken to a page like the following –

In the page, ‘MailChimp Lists’ lets you choose the list where the subscriber should be added to. Then, you have the option to enable or disable double opt-in.
Then, in the ‘Checkbox Settings’ section, you can choose the forms where the checkbox should be added. Below, you will find more options to customize the checkbox label text, pre-check the checkbox and apply default CSS styling.
After making all changes, click ‘Save Changes’. Your checkbox(s) should be in place now.

Using Forms to Increase Subscribers
MailChimp also lets you create a customized subscription form for the visitors. To create a new form, go to MailChimp for WP > Forms from the website dashboard.

First of all, you can apply some basic styling by choosing a color scheme from the ‘Load form styles’ drop-down menu. Then, choose the list where the subscribers should be added to.
Below, you can customize the form from the ‘Form mark-up’ section. By default, the email address and the submit fields are added. To add new fields, generate the HTML code from the ‘Add a new field’ section and paste the code in the mark-up section. You can add fields for first name, last name, subscribe/unsubscribe choice, etc. Each of these options could be made required too. After finishing the customization process, click ‘Save Changes’.
Then, in the ‘MailChimp Settings’ section, you can choose to enable double opt-in for the subscribers. The other two options of this section are available in the pro version only.

In the ‘From Settings & Messages’ section, you will find the option to hide the form once a visitor has signed up to your list. It is also possible to redirect the visitor to a specific page once they have signed up. To do that, provide the destination URL in the ‘Redirect to URL after successful sign-ups’ field.
Below, you will find separate fields to customize the text for different situations like successful subscription, invalid email address, required field missing, already subscribed, general error, unsubscription, etc.
Don’t forget to click ‘Save Changes’ after configuring the options. Here’s a preview of the subscription form with the ‘Red’ color scheme applied.

Final Words
So, that is how you use the MailChimp for WordPress plugin to build up your subscriber list. Let me know if you have any questions about using the plugin. Also, if you are using any other plugin for increasing email subscribers, don’t forget to share your experience with us.