Hello @Jennifer_Shaddox and welcome to the community! 
Based on what you stated, your team is currently set as “Public to organization” which allows any of your 700 employees to join automatically without approval. Here is how you can fix this:
1. Change your Team’s privacy so people cannot self-join
- Open the Team in the sidebar
- Click the team name > Edit Team Settings > Privacy
- Set it to Private if you want invites only
- Or use Membership by request if you are OK approving join requests instead of instant access
2. Restrict who can invite new members
- In Edit Team Settings > Members, set invites to Team admins only
- Remove any folks who “joined independently” and should not be there
Let us know if these worked, Jennifer. But if they didn’t, kindly contact the Support team by following the steps in this guide: How to contact our Support Team
Thank you and have a great Asana day! 
