Yes. When you create an account with Mailytics you will have a 14-day free trial before having to input any billing info. However you will need to input your billing details before the trial ends in order for your account to remain active afterwards. If you don't input any billing information, then after the free trial your account will be deactivated until you provide your card details.
You can enter your card details at anytime by going into your account and accessing the subscription settings page and clicking on "Update Card Details". You can find the Subscription Settings page at Settings > Subscription. After the trial and once you have entered your billing information, your account will be upgraded to the subscription plan you chose during registration.