After having created a poll (with the option 'Everyone with a link can participate' at step 4), Doodle sends or shows you two links. You invite participants by sharing the participation link with them, by e-mail for instance. You can send invitation e-mails out with your regular e-mail program (and the address book you already have).
Or open the admin link of the poll and click 'Invite participants'.
When creating a poll you can invite straight away at wizard step 4. Simply fill in the email addresses into the field below 'Invite participants'. In case you have your addressbook connected you can access your addresses right away.
When typing in the email addresses you need to separate them by comma.
If you don't want to connect your address book but need to use email lists more often you can save your email addresses e. g. in a text file and copy them into the 'Invite participants' field. You need to use the following format:
John Doe <firstname.lastname@example.org>, Jane Doe <email@example.com>
Be aware that you won't receive a general link (which you can send out via email) when choosing 'Only invited people can participate' at step 4. In this case you can only invite with Doodle.