There are occasions in which you collect email addresses from clients opting to receive your email marketing campaigns while being offline. Events or physical stores are good examples of such occasions. If you utilize such an offline subscription method it is important to always hold a copy of the form that the client used in order to subscribe to your newsletter, for safekeeping.
Keep in mind that offline collection can sometimes be tricky as it does not necessarily constitute proof of permission in case a member of your list later claims they never subscribed to it. Similarly, bad handwriting on a physical form means there is ground for mistakes, and sending a campaign to a wrong or non-existent email address hurts both your sending reputation and your campaigns' deliverability rates.
To avoid such issues we highly suggest that you create and embed a subscription form on your website. It is very easy to create your own subscription form with our platform and it will save you the trouble of having to manually add new emails to your email list.