After you selected your contacts it's time to write the personal invitation mail, you can do this just by clicking Next: Compose message or you can select it Compose message is written:
You are free to choose if you select a template from Starred with the standard invitation in your account ‘Example’, but we advise to create your own personal invitations. In order to give it a personal touch, you can customize the preamble, the general text and the text on the Submit Feedback button. You can also start asking one of the form’s questions in your invitation.
After creating your perfect invitation, you can save it as a template. This way, you are able to send the exact same invitation when inviting new contacts for this form. Here are instructions on how to create, copy and change a template:
More information about the advanced settings in the invitation page (adding a question in the text, planning in the batches, etc.) can be found by clicking here.