Hi @kallie and welcome to the forum! Did you send an invitation to the sitter?
If so, they should receive it by email. If they have notifications enabled, they should also receive a notification. It’s important to send a message along with an invitation so the sitter feels that you are connecting with him/her and not just sending a generic invite to several people making it less likely they’ll consider it.
Invitations are generally not the best way to get a sitter. Sitters you contact may not be interested in your location, your pets, the dates may not work, etc. It’s much better if your listing attracts applicants. If you add your listing to your forum profile, forum members will give you helpful feedback and advice to make it stand out. Here are the instructions:
How to add your listing or profile to your forum profile