Firstly, you will need to consider how your invitations are sent, as this will impact the other considerations.
Sending your invitation by post
This is a good choice if you have the budget for printing and postage, you require the invitations to look exclusive and elegant, and you have sufficient lead time. If you plan to post your invitations, due consideration should be given to weight of paper and invitation size in terms of the cost implications for your budget. You can contact people via post without prior consent.
Sending your invitation by email
The invitation will still need to be designed, but can be sent as a jpeg attachment or a gif file in the body of the email itself. If you are lacking time and/or budget for print, materials, and postage (or if your list consists of lots of guests from overseas) this is a good option. It is also a more environmentally friendly option, particularly if you have a large guest list.
Sending your invitation by email is a good choice if you want your guests to sign up for a lecture, for example, online. The Events Office currently use Adestra to design and send the invitations. Guidance about online registration platforms can be found in the event management toolkit.
Under the General Data Protection Regulation it is not acceptable to contact someone via their personal email address or directly via phone if they have not given you prior consent to do this. To obtain consent you can either write to them by post or email a general email address in the public domain (e.g. firstname.lastname@example.org). Further information is available on GDPR and events.