If you're organising a party for a loved one who is moving, you'll need to word the farewell party invitations so that they match the party's level of formality and provide guests will all the necessary details to be a part of the celebration.
If the party will be small and will be held in someone's home, it's acceptable to send informal invitations that are worded something like 'Let's have a taco night at my place to celebrate (guest of honour) before she moves! It's potluck style, so bring your favourite taco toppings and memories of (guest of honour) for an unforgettable night!'
For formal farewell parties that will have a larger guest list, it's best to use wording like 'Join us as we celebrate an evening with (guest of honour).' If the person the party is for will be speaking or performing, this should be included in the invitation as well: '(guest of honour) will be reading an excerpt from her latest work, before we bid her farewell as she transitions to her next professional venture.'
It's best to send invitations to guests at least three weeks before the farewell party, so that attendees can clear their schedules. Provide RSVP wording in the invitations that everyone knows when to confirm their attendance. Since this is a farewell celebration, it's a good idea to ask guests who can't attend to send a farewell card or heartfelt note to the guest of honour at the address you provide.